Update on the latest news, sports, business and entertainment

FINANCIAL MARKETS

UPDATE: US stocks fall for fourth straight day

U.S. stocks fell for the fourth day in a row as concerns about global economic weakness intensified, even as Federal Reserve Chair Janet Yellen reiterated her confidence in the U.S. economy.

Financial stocks fell hardest Thursday as investors worried that interest rates in the U.S. and elsewhere would remain low and sap bank profits. Oil prices sank again, this time to their lowest levels since 2003.

While all three major U.S. indexes finished lower, they recovered somewhat from far steeper losses earlier in the day.

The Dow Jones industrial average fell 254 points, or 1.6 percent, to close at 15,660. The Standard & Poor's 500 index fell 22 points, or 1.2 percent, to 1,829. The Nasdaq composite fell 16 points, or 0.4 percent, to 4,266.

DEM 2016-DEBATE

Clinton, Sanders to debate after splitting contests

MILWAUKEE (AP) — After splitting the first two voting contests, Hillary Clinton and Bernie Sanders are taking their increasingly heated fight for the Democratic presidential nomination back to the debate stage Thursday night. Both candidates are jockeying for an advantage as the race heads toward delegate-rich states.

For Clinton, that means bolstering her appeal with minorities, particularly black and Hispanic voters. Hours before the debate, a coalition of black lawmakers formally endorsed her, calling her a long-term partner who understands racial divides in America.

Sanders, who has demonstrated broad appeal with young voters and liberals, must now prove that he can run a viable campaign outside of the overwhelmingly white states that kick off the nominating process.

CLINTON EMAILS

NEW: Judge orders Clinton's last emails public before Super Tues.

WASHINGTON (AP) — A federal judge has ordered Hillary Clinton's remaining emails from her time as secretary of state to be released by the end of the month, just before the presidential primary day known as Super Tuesday.

The State Department will publish some 550 pages Saturday.

The next installment is set for Feb. 19, a day before Nevada's Democratic caucus. Another comes Feb. 26, a day before South Carolina's primary.

The last of Clinton's 55,000 pages of emails are expected to be made public on Feb. 29. Eleven states will hold a Democratic primary or a caucus on March 1.

Clinton is battling Vermont Sen. Bernie Sanders for the Democratic presidential nomination.

US-VOTING-CITIZENSHIP

NEW: Groups decry US election official acting on citizenship rule

WICHITA, Kan. (AP) — More than 30 advocacy groups are asking a federal elections official to withdraw changes made to a national form requiring residents of Kansas, Alabama and Georgia to provide proof of U.S. citizenship in order to register to vote.

The groups sent a letter Thursday to the new executive director of the U.S. Election Assistance Commission, arguing the impact would be particularly significant because 2016 is a presidential election year when people typically register in greater numbers.

The EAC had no immediate comment, but executive director Brian Newby has insisted that the action he took at the states' request is within his authority.

One of the agency's commissioners has said Newby's action contradicts policy and precedent.

Among those signing the letter were nonprofits Common Cause and Public Citizen and the NAACP.

RANCHING STANDOFF

Last occupier surrenders

BURNS, Ore. (AP) — The occupation of a national wildlife refuge in Oregon is over.

Surrounded by FBI agents in armored vehicles, the last four occupiers surrendered today. They were the last holdouts from a group that had seized the refuge nearly six weeks ago, demanding that the government turn the land over to locals and release two ranchers who'd been imprisoned for setting fires.

The FBI says "no one was injured, and no shots were fired" when all four were taken into custody. The surrender of the holdouts played out live over a phone call streamed online.

Authorities say Sean Anderson, 47; his wife Sandra Anderson, 48, both of Riggins, Idaho; and Jeff Banta, 46, of Yerington, Nevada, were arrested around 9:40 a.m. Thursday.

The FBI says 27-year-old David Fry, of Blanchester, Ohio, who delayed leaving the refuge, was apprehended about 11 a.m.

They all face a federal felony charge of conspiracy to keep federal workers from doing their duties through force or intimidation. The four will appear before a judge in Portland on Friday.

MEXICO-PRISON

52 dead, 12 injured in riot at northern Mexico prison

MONTERREY, Mexico (AP) — A Mexican governor says no escapes have been reported during a brutal fight between rival factions at a prison, which left 52 inmates dead and injured 12 others.

The governor says the battle, which sent flames billowing into the pre-dawn sky, didn't involve guns. It's Mexico's deadliest prison riot in many years. And it comes six days before Pope Francis is scheduled to visit another Mexican prison.

Nuevo Leon Gov. Jaime Rodriguez said at a news conference that the clash involved a faction led by a member of the infamous Zetas drug cartel.

Images broadcast by Milenio Television showed flames leaping from the prison as a crowd of people bundled against the cold gathered outside. Some shook and kicked at the gates, demanding to be allowed in. Rescue workers could be seen bringing injured inmates from the facility, at least some with burns.

CONGRESS-IRAN

US says precise location of Iran's enriched uranium unknown

WASHINGTON (AP) — A State Department official says the U.S. does not know the precise location of tons of low-enriched uranium shipped out of Iran on a Russian vessel under the landmark nuclear agreement.

Testifying Thursday, Ambassador Stephen Mull tells the House Foreign Affairs Committee the stockpile is a Russian custody issue.

Critics of the nuclear deal seized on the shipment's status to show the agreement's flaws. New Jersey GOP congressman Chris Smith says it's "outrageous and unbelievable" that Russia is being trusted to be the repository for such sensitive material. Russia is a close ally of Iran.

The low-enriched uranium is suitable mainly for generating nuclear power and needs substantial further enrichment for use in the core of a nuclear warhead.

Mull says he's confident the material will be controlled properly.

UNITED STATES-AFGHANISTAN

US airstrikes target Islamic State in Afghanistan

WASHINGTON (AP) — U.S. officials say there have been about 20 airstrikes against Islamic State militants in eastern Afghanistan in the past three weeks, as the U.S. expands its fight against the insurgent group beyond Iraq and Syria.

The strikes come in the wake of a decision by the Obama administration to give the Pentagon the authority to conduct airstrikes against IS in Afghanistan. The group's numbers there continue to grow.

Army Brig. Gen. Wilson A. Shoffner says there are 1,000 to 3,000 Islamic State fighters in eastern Afghanistan trying to establish a base.

Shoffner declines to say how many airstrikes the U.S. conducted in the east, but other U.S. officials say it's around 20. The officials aren't authorized to discuss the numbers publicly so spoke on condition of anonymity.

EINSTEIN'S WAVES

Breakthrough: Scientists detect Einstein-predicted ripples

WASHINGTON (AP) — Scientists say they have finally detected gravitational waves — the ripples in the fabric of space-time that Einstein predicted a century ago.

The announcement has electrified the world of physics and astronomy. Scientists say the finding opens a new way of observing the cosmos.

For many years, scientists have had indirect evidence of the existence of gravitational waves rippling across the universe.

But now, an all-star international team of astrophysicists using an excruciatingly sensitive, $1.1 billion instrument has actually detected one of these waves from the distant crash of two black holes.

One theorist says the feat ranks along Galileo taking up a telescope and looking at the planets.

OUR NEANDERTHAL DNA

Study: Neanderthal DNA may influence modern depression risk

NEW YORK (AP) — A new study says a person's risk of becoming depressed or hooked on smoking may be influenced by DNA inherited from Neanderthals.

Researchers found evidence that one bit of Neanderthal DNA can boost the risk of tobacco addiction, while others can slightly raise or lower the risk of being diagnosed with depression.

Modern people with European or Asian roots carry a tiny bit of Neanderthal DNA because their ancestors interbred with Neanderthals about 50,000 year ago. Scientists say studying the effect of that genetic legacy may help them understand the biology of some diseases.

The new work was based on analyzing medical records and genetic information of about 28,000 Americans. It was released Thursday by the journal Science.