This undated handout image provided on May 1, 2008 by IntelCenter shows a video still image of Adan Hashi Ayrow

Islamist militants say they will continue their jihad in Somalia, despite the death of their leader, al-Qaida's chief operator in the country.

A spokesman for the al-Shabab militant group says the group will avenge the death of Aden Hashi Ayro, who was killed Thursday by a U.S. air strike.

Militants and residents of the town of Dusamareb say Ayro, another senior leader and at least 11 other people died in the attack.  Residents say many civilians remain missing.

Ayro trained with al-Qaida in Afghanistan in the 1990s, and was on a U.S. list of suspected terrorists.

His group, al-Shabab, is considered the military arm of the Islamic Courts Union, which controlled much of southern Somalia in 2006.

The group regularly claims responsibility for attacks on Somali government forces and their Ethiopian allies, who together pushed the Islamists from power two years ago.

The United States has designated al-Shabab a terrorist organization and says some of its leaders are affiliated with al-Qaida.

Ethiopia's Information Ministry called the attack on al-Shabab a "remarkable victory" in the battle against terrorism and fundamentalism. The state-run Ethiopian News Agency quotes the ministry as saying the air strike would help put off terrorist attacks and ensure lasting peace in Somalia.

Some information for this report was provided by AFP, AP and Reuters.