A strong earthquake measuring 5.9 struck the U.S. east coast on Tuesday, rattling buildings in downtown Washington and causing evacuations of buildings as far away as New York.

The Pentagon was evacuated after the region's rare temblor, which according to the U.S. Geological Survey had its epicenter near Richmond, Virginia.

The Pentagon believes Libya's Moammar Gadhafi has not fled the country, a military spokesman said Monday, as rebel forces swept into the Libyan capital.

It's "probably fair to say that we believe he's still in the country," spokesman Colonel Dave Lapan told reporters.

U.S. Secretary of State Hillary Clinton said Sunday she was "deeply disappointed" over the eight-year prison sentence given to two Americans who have said they had strayed unwittingly into Iran.

"We are deeply disappointed that Iranian judicial authorities have sentenced Shane Bauer and Joshua Fattal to eight years in prison," Clinton said.

The United States and Iraq have not yet agreed to a post-2011 American military training mission, an aide to the Iraqi premier said Friday, after the U.S. defense chief said Baghdad had given the okay.

"We have not yet agreed on the issue of keeping training forces," Ali Moussawi, media advisor to Prime Minister Nouri al-Maliki, told Agence France Presse.

The staff of the U.S. Treasury Department, which is in charge of following up on the financial activities of Syrian President Bashar al-Assad’s family and entourage, believe that they are getting closer to unveiling a link between Assad’s financial interests and Premier Najib Miqati and his brother Taha, who is also a businessman.

According to a U.S. report to be published Friday by the Kuwaiti daily al-Rai, the set of sanctions recently imposed on Syriatel -- Syria’s largest mobile phone operator owned by Assad’s cousin Rami Makhlouf -- were supposed to be expanded to include either Miqati or his brother Taha for their role in establishing the Syrian firm and introducing the cellphone technology to the Syrian market more than a decade ago.

U.S. President Barack Obama demanded Thursday that Syrian President Bashar al-Assad "step aside" and imposed tough sanctions on Damascus including an asset freeze and ban on U.S. investments in Syria.

"We have consistently said that President Assad must lead a democratic transition or get out of the way. He has not led. For the sake of the Syrian people, the time has come for President Assad to step aside," Obama said.

The FBI is investigating allegations that Syria is intimidating and threatening dissidents in the United States, according to U.S.-based Syrians who say federal agents have questioned them.

Three dissidents who met with U.S. Secretary of State Hillary Clinton in Washington two weeks ago told Agence France Presse that FBI agents raised concerns about their safety and asked who might be behind the campaign.

The Taliban blamed the state of the U.S. economy and last week's London riots on the war in Afghanistan in a statement published on its website Monday.

The insurgents claimed both situations were linked to the U.S. and Britain spending hundreds of billions of dollars on the ten-year war in Afghanistan and again urged foreign troops to pull out of the country.

U.S. Secretary of State Hillary Clinton, asked why Washington has not yet explicitly called for the Syrian president’s departure, said Thursday her country wanted such a call to come from “around the world,” not just from the White House.

“What we really need to do to put the pressure on Assad is to sanction the oil and gas industry. And we want to see Europe take more steps in that direction. And we want to see China take steps with us,” Clinton added in an interview with CBS News.

The United States on Wednesday imposed sanctions on Syria's largest commercial bank and largest mobile phone operator, stepping up the pressure on the regime of President Bashar al-Assad.

The moves targeting the state-owned Commercial Bank of Syria, its Lebanon-based subsidiary and telecoms company Syriatel are the latest taken by Washington against Syria over its crackdown on anti-regime protests.