U.S. Defense Secretary Chuck Hagel said Tuesday he had ordered top military commanders worldwide to be on high alert over the imminent publication of a report on the CIA's use of torture.

"I have ordered all our combatant commanders to be on high alert everywhere in the world," he told reporters in Baghdad, adding however that no specific threat had been reported.

Ukraine and pro-Russian insurgents on Tuesday were preparing to put to the test a comprehensive ceasefire aimed at calming an upsurge of violence that has eroded trust between Moscow and the West.

Uncertainty swirled around the deal in the early morning hours on what the government has dubbed "a day of silence." 

Iraqi Prime Minister Haider al-Abadi appealed to U.S. Defense Secretary Chuck Hagel on Tuesday for more air raids from Western warplanes and more arms to take on the Islamic State group.

"Our forces are very much advancing on the ground. But they need more air power and more ... heavy weaponry. We need that," Abadi told Hagel at the start of their talks in the Iraqi capital.

A small jet airplane crashed Monday into a residential neighborhood near the US capital, killing six people.

The Embraer EMB-500 twin-engine jet was a mile away from Montgomery County Airport, preparing to land, when the accident occurred, according to a statement from the Federal Aviation Administration.

U.S. Secretary of State John Kerry Monday vowed the world was on its way towards getting rid of the scourge of landmines, backed by major U.S. efforts over the past decades.

Even though America is not a signatory of the Convention to ban landmines, "the United States, we can proudly say, has played a very important role in this," Kerry said, unveiling the 2014 report detailing the work done by the State Department's bureau of political-military affairs.

The U.S. Senate will release a long-delayed report Tuesday into the CIA's brutal interrogation of al-Qaida suspects following the 2001 attacks, as American interests abroad take precautions ahead of a possible backlash.

White House officials confirmed Monday they expect the report to be published, even though U.S. Secretary of State John Kerry warned late last week about the impact it could have around the world.

The United States embassy in Sri Lanka denied on Saturday it was "pumping money" into the country to topple President Mahinda Rajapakse after the allegations were leveled by a minster.

Resettlement minister Gunaratne Weerakoon accused U.S. envoy Michele Sison of seeking to fund opposition forces in the election campaign in order to oust Rajapakse who is seeking an unprecedented third term in next month's elections.

Drone strikes killed nine suspected al-Qaida militants Saturday in southeast Yemen, where the U.S. military launched a failed operation last month to rescue an American hostage, security and tribal sources said.

"Several drone strikes have targeted al-Qaida positions in Nusab (in Shabwa province), killing nine members of the network," a security source told AFP.

A U.S. Navy civilian engineer was arrested Friday on charges of trying to steal schematics of a new nuclear aircraft carrier and have them sent to Egypt, the Justice Department said.

An undercover FBI agent posed as an Egyptian intelligence officer to snare Mostafa Ahmed Awwad, 35, from the state of Virginia, who is charged with two counts of attempting to export defense articles and technical data.

Thousands of demonstrators marched in major cities across the United States on Friday in a fresh wave of protest against the killing of unarmed black men by white police officers.

The latest rallies in a fortnight of growing discontent took place as a New York prosecutor said he would impanel a grand jury to consider charges in one of the cases that has again brought to the fore the distrust felt by many African Americans towards the police.