Dubai: 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.

Last week his father called for his son's teaching to be continued and his death avenged.

Nassar al Awlaki, the father of Anwar, the al Qaeda in the Arabian Peninsula ideologue who was involved in operations before he was killed by the US, spoke out against the deaths of his son and grandson and urged Muslims to continue to spread his son's message that advocated jihad against the West.

Nassar, an influential figure in Yemen, made the statement in a 6-minute, 37-second audio that was released on YouTube by Anjem Choudary, a radical Islamist preacher in Britain who leads the banned group Muslims Against Crusades. [The video can be seen in full above.] A transcript of Nassar's audiotape was provided by the SITE Intelligence Group.

In the statement, the senior Awlaki did not express remorse for his son's radical sermons, which advocated that Muslims kill Americans and Westerners, but instead referred to his son reverently. Nassar described Anwar as his "beloved son" and "Imam" who "carried an effective message, a message that was simple and straight-forward. Its [Anwar's message] target were Muslims in the West," Nassar said. "They [the US] considered a fluent, convincing Muslim preacher as a threat, so they tried everything to silence him."

Meanwhile; A new video released by the Yemeni wing of al Qaeda includes a mysterious English speaker in what could be the debut of a new spokesman to replace Anwar al-Awlaki. The video, posted by al Qaeda in the Arabian Peninsula's media arm, is a commemoration of al-Awlaki, who was killed by a U.S. drone strike last September. It includes new footage of al-Awlaki lecturing.

The mystery man, Abu Yazeed, appears twice in the video. He is in shadow, peering off camera, and is wearing glasses and has a full beard. He is wearing what appears to be a black-and-white turban. He is identified as "Brother: Abu Yazeed." In the video, Abu Yazeed speaks with an accent. He criticizes the U.S. for targeting Muslims as it fights terrorism, referencing the killings of al-Awlaki and American Samir Khan, who was killed in the same strike, and al-Awlaki's son, who was killed in a separate strike. The appearance of Abu Yazeed could be significant. The killings of al-Awlaki and Khan were considered a major blow to the terror group’s efforts to appeal to Westerners.

"This is the first time an English speaker has appeared in an AQAP video other than al-Awlaki and is likely to mark his addition to the face of AQAP," said Ben Venzke of IntelCenter, who analyzes terrorist communications. Venzke said that Abu Yazeed could be used the way that al Qaeda in Pakistan uses Adam Gadahn: to deliver a message to Westerners. No articles about Yazeed appear in past issues of Inspire, said Adam Raisman, an analyst at the SITE intelligence group, who did a search for Security Clearance. Raisman said the name was probably a “nom de guerre.”

Raisman said it was possible that AQAP was trying to debut him in connection with al-Awlaki, who held strong appeal to some Westerners. The U.S. government considered him a threat because of how influential he was in appealing to those in the West and recruiting jihadists. They could be showing that despite killing al-Awlaki, "there are other English speakers" in AQAP "who can appeal to a Western audience," Raisman told CNN. He said it remains to be seen in future releases whether he truly is the new spokesman.