LONDON, Feb. 10 (UPI) -- An announcement from al-Qaida that Somalia's al-Shabaab was a formal affiliate confirms what most analysts already know, a U.S. official said.
Al-Qaida leader Ayman al-Zawahiri announced in a video message posted on Islamic Web forums that al-Shaabab's alliance with al-Qaida should "disturb the disbelievers."
A U.S. official was quoted by The Daily Telegraph newspaper in London as saying the announcement about al-Shabaab wasn't much of a surprise.
"Zawahiri's announcement just formalizes what everyone already knew: al-Shabaab is an affiliate of al Qaida," the official said on condition of anonymity. "This doesn't change the fact that al-Qaida's core is still suffering and trying to remain relevant."
Zawahiri assumed control over al-Qaida after Osama bin Laden was killed by U.S. forces in May.
U.S. intelligence officials said al-Qaida central was weakened by bin Laden's death but stressed al-Qaida affiliates like al-Shabaab, the Yemeni branch and the North African wing are emerging concerns.
Al-Shabaab voiced allegiance to al-Qaida more than two years ago and expressed its support for Zawahiri when he assumed command over al-Qaida central.
Al-Shabaab is fighting for control over Somalia. The interim government in Mogadishu has made gains against the group but struggles to exert its authority much beyond the capital city.
There is an international conference on Somalia this month in London.