US-born al-Qaeda militant Anwar al Awlaki, killed in a CIA drone strike in September, posthumously called on US Muslims to join the group in the Middle East in a video released on Tuesday.
Awlaki, identified by US intelligence as "chief of external operations" for al-Qaeda's Yemeni branch and a Web-savvy publicist for the Islamist cause, was killed in a remote Yemeni town by missiles fired from multiple CIA drones.
"You have two choices: either hijra [emigration] or jihad [holy war]," Awlaki said in the video, which was posted on Islamist websites.
"I specifically invite the youth to either fight in the West or join their brothers in the fronts of jihad: Afghanistan, Iraq, and Somalia.
"I invite them to join us in our new front, Yemen, the base from which the great jihad of the Arabian Peninsula will begin, the base from which the greatest army of Islam will march forth," said Awlaki, a cleric of Yemeni descent, speaking in English.
Awlaki was implicated in a failed attempt by al-Qaeda in the Arabian Peninsula to bomb a US-bound airliner in 2009, and he had contacts with an American army psychiatrist who killed 13 people at a US military base the same year.
The video included a message to the American people issued by Awlaki in March 2010. But the SITE monitoring service, which tracks jihadist statements, said Awlaki's call to join al-Qaeda abroad had not appeared on that tape, although it has since been referred to in an online magazine of al-Qaeda's Yemeni wing.
In November, New York police arrested a follower of Awlaki on suspicion of building a pipe bomb to use against US soldiers returning from Iraq and Afghanistan.
Eloquent in English and Arabic, Awlaki encouraged attacks on the United States and was seen as a man who could draw in more al-Qaeda recruits from Western countries.
In Boston, a jury on Tuesday found a Massachusetts man guilty of supporting al-Qaeda by translating Arabic messages and supporting militants travelling to Yemen for training.
In Yemen, gunmen shot dead an intelligence officer in the southern province of Lahej, a security official said, adding that al-Qaeda was believed to be responsible.
Separately, security forces arrested seven alleged al-Qaeda members who were planning attacks on government installations and officials in the south, the Defence Ministry said.
The men were detained in the town of Ataq, near Abyan province, where militants linked to al-Qaeda have seized swathes of territory and challenged a peace accord aimed at pulling the poor country away from civil war.
The deal, brokered by Yemen's richer Gulf neighbours, aims to end a political crisis in which protests have raged for 11 months of protests against President Ali Abdullah Saleh.
Top oil exporter Saudi Arabia shares US fears that more instability in Yemen could embolden al-Qaeda militants there - seen by Washington as the group's most dangerous branch - in a country sitting next to oil shipping routes.
Since Saleh handed over his powers to his deputy under the Gulf peace accord, a new government headed by an opposition leader has been formed. A presidential election is set to be held in February.
Apart from Islamist militants, the new government is facing challenges from a southern separatist movement and a Shi'ite Muslim rebellion in the north.