A gunman shot and killed a senior Yemeni politician after he spoke as a guest at an Islamic party's congress Saturday, security officials said.

Jarallah Omar, the deputy secretary-general of the Yemeni Socialist Party, was shot minutes after he delivered a speech at the annual congress of the Islamic Reform Party in the capital, San'a.

Omar died of his wounds on the way to hospital, said Seif Tayel, a Socialist party official. In a statement, the party condemned the shooting as a "politically-motivated assasination."

A senior official in the Islamic Reform Party said the attacker apparently shot Omar because of the politician's secular ideology.

An Interior Ministry official identified the assailant as Ali al-Jarallah and said he was a member of the Islamic Reform Party, the official Yemeni news agency Saba reported.

The Islamic Reform Party denied he was a member.

After the shooting, the attacker was taken by special security agents of the Reform party's leader, Abdullah al-Ahmar, to al-Ahmar's home where he was questioned before being handed over to the Interior Ministry, party and security officials said.

During the questioning, al-Jarallah said people like Omar belonged to "secular infidel parties and had to be killed," an official in the Islamic Reform Party said on condition of anonymity.

Al-Ahmar, whose party is the second biggest in the legislature, is also the Parliament speaker.

Another security official, also requesting not to be named, said al-Jarallah had recently been released from prison where he served six months for delivering an anti-government speech.

Omar was one of several leaders of rival parties that had been invited to address the Islamic Reform party assembly. His Socialist party is regarded as the most popular opposition group in Yemen, but it is not represented in parliament because it boycotted the last elections, held in 1997.

The Socialists ruled the southern part of Yemen before the two halves of the country united in 1990.

When leftist southerners rebelled in 1994, President Ali Abdullah Saleh formed an alliance with Islamic militants and fundamentalists to defeat them. He brought the Islamic Reform party into a coalition government.