• Activists declare east Ukrainian area independent

DONETSK, Ukraine - Pro-Moscow activists barricaded inside government buildings in eastern Ukraine proclaimed their regions independent Monday and called for a referendum on seceding from Ukraine - an ominous echo of the events that led to Russia's annexation of Crimea.

The Ukrainian government accused Russia of stirring up the unrest and tried to flush the assailants from some of the seized buildings, setting off fiery clashes in one city. Russia, which has tens of thousands of troops massed along the border, sternly warned Ukraine against using force.

In Washington, the U.S. said any move by Russia into eastern Ukraine would be a "very serious escalation" that could bring further sanctions. White House spokesman Jay Carney said there was strong evidence that some of the pro-Russian protesters were hired and were not local residents.

• Army: Rampage related to leave request dispute

FORT HOOD, Texas - Army investigators on Monday released a more detailed timeline of last week's fatal shootings at Fort Hood, describing an eight-minute rampage in which the suspect fired 35 shots over an area spanning the equivalent of two city blocks.

Three people were killed and 16 others wounded in the shooting spree before the suspect, Spc. Ivan Lopez, killed himself, authorities said.

During a news conference Monday, Army spokesman Chris Grey said the shootings at the Texas post followed an argument related to Lopez's request for taking leave, but he didn't indicate whether it was granted or describe circumstances behind the request.

A spokesman for Lopez's family said last week that Lopez was upset he was granted only a 24-hour leave to attend his mother's funeral in November. That leave was then extended to two days.

• Search focuses on whether pings are from plane

PERTH, Australia - Search crews were for the first time sending a sub deep into the Indian Ocean to try and determine whether faint sounds detected by equipment on board an Australian ship are from the missing Malaysia Airlines plane's black boxes, Australia's acting prime minister said Tuesday.

Warren Truss, Australia's acting prime minister while Tony Abbott is overseas, said the crew on board the Ocean Shield will launch the underwater vehicle, the Bluefin 21 autonomous sub, on Tuesday. The unmanned miniature sub can create a sonar map of the area to chart any debris on the sea floor. If it maps out a debris field, the crew will replace the sonar system with a camera unit to photograph any wreckage.

Angus Houston, who is heading the search, said Monday that the Ocean Shield, which is towing sophisticated U.S. Navy listening equipment, detected late Saturday and early Sunday two distinct, long-lasting sounds underwater that are consistent with the pings from an aircraft's "black boxes" - the flight data and cockpit voice recorders. Houston dubbed the find "a most promising lead" in the monthlong hunt for clues to the plane's fate, but warned it could take days to determine whether the sounds were connected to Flight 370.

Crews have been trying to re-locate the sounds since Sunday, but have thus far had no luck, Truss said.

"Today is another critical day as we try and reconnect with the signals that perhaps have been emanating from the black box flight recorder of the MH370," he said. "The connections two days ago were obviously a time of great hope that there had been a significant breakthrough and it was disappointing that we were unable to repeat that experience yesterday."

• Senate clears jobless-benefits legislation

WASHINGTON - The Senate voted 59-38 Monday to resurrect federal jobless benefits for the long-term unemployed, and a small band of Republican supporters swiftly appealed to a reluctant Speaker John Boehner to permit election-year action in the House as well.

Steps are needed "to restore unemployment benefits to struggling Americans," seven House Republicans wrote Boehner and Majority Leader Eric Cantor of Virginia. They released their letter as the Senate was bestowing its widely expected approval on the legislation.

Despite the appeal, the bill's prospects are cloudy at best, given widespread opposition among conservative lawmakers and outside groups and Boehner's unwillingness to allow it to the floor without changes that Republicans say would enhance job creation.

- Associated Press