An unemployed Yemeni man tossed one or two sound grenades at the U.S. Embassy in San'a on Friday, hitting a wall but injuring no one, Yemeni and U.S. officials said. The attack came a day after Vice President Dick Cheney visited Yemen.

A U.S. Embassy spokesman said two grenades were thrown but caused no injuries or damage. "They were noisemakers" rather than weapons, hs pocket when Yemeni security guards outside the embassy opened fire and arrested him. It was not immediately known whether he was wounded by the gunfire, they added, speaking on condition of anonymity.

The alleged attacker was a 25-year-old high school dropout named Samir Yahya Awadh, according to Faris Sanabani, editor of the government-owned Yemen Observer newspaper. Awadh was unemployed and has no known political affiliations, Sanabani added.

An Interior Ministry statement said his family had described as psychologically disturbed.

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 comes a day after Cheney visited San'a airport for two hours of talks with Yemeni President Ali Abdullah Saleh on the war on terrorism.

Cheney was notified about the embassy incident, which people traveling with Cheney in Oman on Friday characterized as an isolated incident, a U.S. official said, speaking on condition of anonymity.

Security in Yemen has been a top concern of the United States since a boat laden with explosives slammed into the USS Cole in October 2000, killing 17 American sailors in an attack the United States links to Usama bin Laden. The destroyer was on a routine refueling stop in Aden harbor.