Thousands of protesters gathered outside the White House Saturday to demand that the United States "stop the massacre in Syria," where an estimated 8,000 people have been killed in a regime crackdown.

Wearing T-shirts declaring "I have a dream of a free Syria" and "No longer afraid," the demonstrators -- who numbered 4,000, according to organizers -- were marking the first anniversary of a bloody revolt against President Bashar Assad's regime.

North Korea said Saturday it would invite foreign experts and journalists to observe a satellite launch which the United States and other countries see as a disguised missile test.

The Korean Committee for Space Technology "will invite experienced foreign experts on space science and technology and journalists" to visit the launch site and other places to observe the blast-off next month, the official news agency said.

The United States said Friday it is concerned about Iranian cargo flights over Iraq to Syria, saying it has warned Iraq they might contain arms that could be used by Damascus to crush protests.

"Without getting into intelligence matters, we are concerned about the overflight of Iraq by Iranian cargo flights headed to Syria," State Department spokeswoman Victoria Nuland told reporters.

The U.S. military said Friday that an attack at a NATO base in Afghanistan this week targeted a top American commander, just as Defense Secretary Leon Panetta flew in for a visit.

After having downplayed the incident, officials released information that showed Wednesday's attack at British-run Camp Bastion in Helmand province was much more serious than initial accounts suggested.

U.S. Vice President Joe Biden, throwing punches as a warrior for the middle class, plunged into the 2012 election race Thursday, hailing President Barack Obama as a man with "steel in his spine."

With Republicans still haggling over their candidate for November's vote, Biden launched a new phase of the Democrats' campaign for Obama, with a fiery speech in the swing state of Ohio, which often decides U.S. elections.

The Taliban said Thursday it had suspended contacts with the United States in Qatar, just days after an American shooting spree left 16 Afghans dead, dealing a blow to hopes of a peace process.

"It was due to their alternating and ever-changing position that the Islamic Emirate was compelled to suspend all dialogue with the Americans," a statement posted on the Taliban website said, making no mention of Sunday's murders.

The U.S. State Department has hailed the efforts exerted by March 14 opposition political leaders to maintain security and expressed support for a new era in Lebanese-Syrian relations.

“We support Lebanon’s political leaders’ efforts to maintain security and to prepare for the day when a democratic government in Damascus will usher in a new era in Lebanese-Syrian relations,” said the State Department on the occasion of the anniversary of the 2005 Cedar Revolution.

Azerbaijan has arrested 22 people on suspicion of plotting attacks on the U.S. and Israeli embassies in Baku on behalf of neighboring Iran, the national security ministry said Wednesday.

"Twenty-two citizens of Azerbaijan have been arrested by the national security ministry for cooperating with the Iranian Sepah," its statement said, referring to the elite Iranian Revolutionary Guards.

A roadside bomb attack killed eight civilians in Helmand on Wednesday as U.S. Defense Secretary Leon Panetta was visiting troops in a military camp in the southern Afghan province.

"A roadside mine planted by the Taliban blasted in Marja district when a minivan touched it, triggering a big explosion. As a result eight civilians were killed," provincial spokesman Daud Ahmedi told Agence France Presse.

U.S. senators are urging the Pentagon to cancel a contract with a Russian company approaching $1 billion to buy helicopters for Afghanistan, voicing outrage over Moscow's arming of Syria.

"U.S. taxpayers should not be put in a position where they are indirectly subsidizing the mass murder of Syrian civilians," 17 senators across party lines wrote Monday in a letter to Secretary of Defense Leon Panetta.