Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. Al-Shabab Leader: Uganda Bombings 'Only the Beginning' VOA News 15 July 2010 Damaged chairs and tables amongst the debris strewn outside the restaurant "Ethiopian village" in Kampala, Uganda, Monday, July 12, 2010 after an explosion at the restaurant late Sunday Photo: AP Damaged chairs and tables amongst the debris strewn outside the restaurant 'Ethiopian village' in Kampala, Uganda, 12 Jul 2010 The leader of the Somali Islamist militant group claiming to be behind the deadly bombings in Uganda says his group is planning more attacks. Sheik Muktar Abu Zubayr thanked the bombers responsible for killing more than 70 people watching the World Cup final on television in Uganda's capital, Kampala. Abu Zubayr's audio message was played on radio stations Thursday in Somalia's capital, Mogadishu. He said his al-Shabab organization will continue to take revenge against Ugandans for their participation in the African Union peacekeeping force in Somalia. Al-Shabab and other militant groups have been fighting for more than three years to take control of Somalia in a civil war that has killed thousands and displaced hundreds of thousands more. But this was al-Qaida-linked group's first major terrorist attack outside of Somalia. Uganda said Thursday it is willing to send 2,000 more troops to join AU peacekeepers in Somalia. In an interview Wednesday, U.S. President Barack Obama said the bombings show extremist militant groups have a vision of "destruction and death" for Africa. Ugandan authorities say they have arrested four foreigners in connection with an unexploded suicide bomb vest found at a third site. They would not say their nationalities, but Negussie Balcha, the head of an organization called the Ethiopian Community in Uganda, told VOA's Horn of Africa Service that four Ethiopians are in custody for questioning. The White House says the FBI is helping Ugandan authorities in the investigation. Ugandan police say a Ugandan Muslim militant group - the Allied Democratic Forces - may have had a role in Sunday's attacks. Most of those who died were watching the World Cup on big-screen televisions Sunday at a rugby club in Kampala. The others died in a blast that targeted an Ethiopian restaurant. Police said at least 60 of the victims in Sunday's bombings were Ugandans. The others included people from Ethiopia or Eritrea, one American aid worker, an Irish woman and one Asian. Some information for this report was provided by AFP and AP. .