A senior Yemeni opposition politician, Jarallah Omar, has been shot dead during a conference in the capital, Sanaa.

Mr Omar, the deputy secretary-general of the Yemeni Socialist Party, had been addressing the annual congress of the Islamic Reform Party, which is also in opposition.

The gunman went up to Omar after he sat down and shot him several times Eyewitness

Security forces arrested the suspected gunman and cordoned off the sports hall were the meeting was taking place, reports say.

Yemeni President Ali Andullah Saleh said Mr Omar was a "victim of violence and extremism", the country's official news agency, Saba, reported.

An interior ministry official identified the gunman as Ali al-Jarallah, of the Islamic Reform Party, Saba said.

The party denied Mr al-Jarallah was a member.

The motive for the shooting is not clear.

Awash with weapons

Mr Omar was one of several leaders of rival parties invited to speak at the conference.

Yemen TV showed pictures of the alleged assassin being tackled

"The gunman went up to Omar after he sat down and shot him several times," Reuters news agency quoted one witness as saying.

Yemen is awash with weapons - according to official estimates there are about 60 million firearms in private hands.

The Socialist Party is the main opposition movement in Yemen.

It was the only party in the former Republic of South Yemen until the unification of the country in 1990.

Its attempt to bring about a new secession of the south in 1994 was crushed by the northern army of President Ali Abdallah Saleh.