A university student threw a hand-grenade at the US Embassy in the Yemeni capital San'a tonight, hitting a tree but injuring no one.
Samir Yahya Awadh, was arrested by security personnel within moments as he was reaching in his pocket for another grenade, said a Yemeni official.
A State Department spokesman in Washington said the explosion was a block or so from the embassy.
Yemeni police and soldiers closed off streets around the embassy and searched vehicles. Witnesses had reported seeing a car speeding from the site after the explosion.
The blast came a day after US Vice President Mr Dick Cheney visited San'a airport for two hours of talks with Yemeni President Ali Abdullah Saleh on the war on terrorism.
Security in Yemen has been a top concern of the United States since a boat laden with explosives slammed into the destroyer Cole in October 2000, killing 17 American sailors in an attack the United States links to Osama bin Laden. The destroyer was on a routine refuelling stop in the port of Aden.
AP