Al-Jazeera aired video it said showed the moments after the attack
A double car bomb attack on the US embassy in Yemen has killed at least 16 people, Yemeni officials say.
Washington said bombers targeted the main security gate as staff were arriving for work, but they failed to breach the compound's walls.
The militants, who were reportedly dressed as policemen, also exchanged gunfire with guards during the assault.
The US blamed al-Qaeda for the attack, and President George Bush said it was a reminder that the US is at war.
Security sources said six members of the Yemeni security forces, six attackers, and four bystanders were killed in the attack, which occurred in the capital, Sanaa, at about 0830 (0530 GMT).
US officials have confirmed that none of the casualties were Americans
Speaking in Washington, Mr Bush said the attack was "a reminder that we are at war against extremists who will murder innocent people to achieve their ideological objectives".
Mr Bush said the US government wanted people to be able to lead normal lives and would "help governments survive the extremists".
Condemning the "vicious" attack, State Department spokesman Sean McCormack said it bore "all the hallmarks of an al-Qaeda attack".
Separately, White House spokesman Gordon Johndroe said the US would continue working with Yemen's government to "increase our counter-terrorism activities to prevent more attacks from taking place".
British citizen Trev Mason described hearing explosions while in his residential compound near the embassy.
"We heard the sounds of a heavy gun battle going on," he told CNN television.
"I looked out of my window and we saw the first explosion going off, a massive fireball very close to the US embassy."
The attack is the second on the embassy in the past six months.
Earlier this year, the US ordered the evacuation of non-essential personnel from Yemen after mortar bombs were fired towards the embassy. They missed but hit a nearby school.
A group calling itself the Islamic Jihad in Yemen said it had carried out the attack, and threatened to target other foreign missions in the region unless its jailed members were released.
The authenticity of the claim could not be immediately verified.
Sean McCormack said he understood that two vehicle-borne bombs had been involved in Wednesday's attack.
"They didn't succeed in this case, and it's a testament again to the kind of security upgrades that we have put in place," he said.
"We are looking at what further security steps we might take in the coming days to make sure the embassy is protected."
Yemen has long been a haven for Islamist militants.
In 2000, 17 US sailors were killed when suicide bombers with alleged links to al-Qaeda blew themselves up on an inflatable raft next to the USS Cole in the Yemeni port of Aden.
The government of Yemen, which backs America's "war on terror", has often blamed al-Qaeda for attacks on Western targets in the country.
US special forces have been helping the government fight the Islamist militants, but analysts say there has been only limited success in restraining the militant groups.
Yemen is a desperately poor corner of the Middle East and, like Afghanistan, there is rugged mountainous terrain, with a vast supply of weapons.