11.   -- The Bureau of Alcohol, Tobacco and Firearms sent two teams of explosives and arson experts to investigate the blast.

12.   A government commission was set up to investigate the blast.

13.   A police official investigating the blasts, speaking on condition of anonymity, said the main explosion was triggered by a timing device.

14.   A statement from the presidential palace said Estrada told the army to help police investigate the blasts.

15.   Authorities are investigating the blast, the agency said, but did not give its cause.

16.   Authorities were investigating the blast, and there were no reports of anyone claiming responsibility.

17.   Authorities were investigating the blast, including whether the U.N. workers were the intended targets, he said.

18.   Authorities were investigating the blast, including whether the U.N. workers were the intended targets, Toure said.

19.   Berisha, in a statement on Monday, urged the state prosecutor to immediately start investigating the blast and punish those responsible.

20.   Berisha urged the state prosecutor on Monday to immediately start investigating the blast and punish those responsible.