Philippine security forces are on alert for possible attacks in Manila after reports one of Asia's top terrorist suspects may have deployed bombing teams to the capital.

Intelligence reports seen by Western journalists did not specify possible targets Islamist militants might have, and the government has not commented on Western news accounts . One document warned of possible bombings on June 12, when the country celebrated its Independence Day, but no attacks were reported.

Another file said fugitive terrorism suspect Zulkifli bin Hir, also known as Marwan, recently ordered bombing teams from the southern island of Jolo to the capital, where they were joined by other militants suspected of earlier bombings in the city.

The heightened alert reported Thursday follows a U.S. State Department travel warning for the Philippines earlier this week, saying terrorist attacks could occur both in the restive southern Philippines and in Manila. The U.S. embassy warning did not cite any specific reason for its most recent alert.

Zulkifli bin Hir, a U.S.-trained Malaysian engineer, is accused by Manila and Washington of involvement in a number of deadly Philippine bombings, and is thought to have operated in the Philippines since 2003. The United States has offered a $5 million reward for his capture.

The U.S. travel alert requires U.S. government employees to gain special permission before traveling to the southern island of Mindanao or the Sulu Archipelago.