A gunman has opened fire outside the US embassy in the Yemeni capital Sanaa, before being shot by security forces and arrested, Yemeni officials say.

No embassy staff were injured in the incident outside the well fortified and heavily guarded compound.

The suspect was taken to hospital and will be interrogated, officials said.

The Yemeni authorities have cracked down on Islamic extremists linked to al-Qaeda since attacks began against western targets six years ago.

Reports say the embassy appeared closed to the public and US officials were not immediately available for comment.

The gunman appeared to be acting alone and was armed with an AK-47 assault rifle. His motive was not clear, the officials said.

He was unable to breach the first of three security lines around the embassy in an eastern suburb of Sanaa.

Yemen's government is a staunch backer of the US campaign against international terrorism and received military aid from Washington.

Photo Caption

The map of Yemen