The U.S. Justice Department is reported to have plans to announce charges against five Philippine rebels, who are linked to al Qaeda, in connection with last month's killing of a kidnapped American missionary.
Martin Burnham, 42, was killed, but his wife, Gracia, 43, was rescued by Philippine troops in a gun battle with Abu Sayyaf rebels in the Philippine jungle. Filipina nurse Deborah Yap was also killed in the clash.
The United States has linked Abu Sayyaf to Osama bin Laden's al Qaeda network and has offered a reward of up to $5 million for information leading to the arrest or the capture of five Abu Sayyaf commanders.
More than 1,000 US troops are to end a six-month counter-terrorism operation next week in the southern Philippines where they have been helping local forces hunt the Abu Sayyaf.
Philippines President Gloria Macapagal Arroyo has come under severe criticism for the move, which nationalists say undermines the sovereignty of the Philippines.
U.S. Secretary of State Colin Powell is set to discuss possible new joint counter-terrorism operations between US and Filippino forces during his visit in August.
Mr Powell is expected in Manila on August 2-3, after attending a foreign ministers' meeting of the Association of Southeast Asian Nations (ASEAN) in Brunei later this month.
