Philippine National Police Special Action Forces and SOCO (Scene of the Crime Operatives) investigators examine the site on the island province of Jolo in southern Philippines.

Philippine National Police Special Action Forces and SOCO (Scene of the Crime Operatives) investigators examine the site on the island province of Jolo in southern Philippines.

MORE than a dozen terrorists, including three of the top leaders of the Jemaah Islamiyah network, have been killed in a pre-dawn air strike on a remote southern Philippine island, security officials say.

If confirmed, the deaths of Zulkifli bin Hir and other leaders of the al-Qaeda-linked group will be a big blow to the network responsible for many attacks and kidnappings in south-east Asia, including the Bali bombings.

Mr Zulkifli's death would represent the most important success against Jemaah Islamiyah since the arrest in January last year of Indonesian terrorist Umar Patek in Pakistan. Mr Zulkifli and Mr Patek are believed to have collaborated to train other militants.

The US lists Mr Zulkifli, a Malaysian who uses the name Marwan, among its most wanted terrorists, identifying him as a member of Jemaah Islamiyah's central command. It had posted a $US5 million ($4.7 million) reward for his capture.

In Washington, US officials confirmed US counter-terrorism forces had provided assistance in what appears to be one of the region's most successful anti-terrorist operations in years.

About 600 US troops are deployed in the southern Philippines to assist ill-equipped local forces. About 30 militants are believed to have been at a hide-out and training camp when two aircraft dropped 227-kilogram bombs at 3am. Mr Zulkifli is believed to have been in a hut that took a direct hit in the air strike.

Mr Zulkifli, who was taught engineering in the US, has been accused of training terrorist organisations including Abu Sayyaf, the group which has demanded a $2 million ransom for Sydney man Warren Rodwell.

Randolph Cabanbang, a southern Philippines military spokesman, said Mr Zulkifli and other ''notorious terrorist leaders'' were killed in the attack on the island of Jolo, a stronghold of Islamic separatist terrorists.

''Their deaths will weaken the capabilities of the Abu Sayaaf,'' Lieutenant-Colonel Cabangbang said. Philippine officials also named Abu Sayaaf leader Umbra Jumdail and his son as among those killed.

Officials said the US-backed strike by Philippine security forces near the town of Parang also killed another Jemaah Islamiyah leader, Abdullah Ali, a Singaporean who goes by the name Muawiyah and who is also on the US's most wanted list.

Security officials are still working to verify the identities of those killed. In the past, some reported killings of terrorists have turned out to be untrue.

But Colonel Cabangbang said the Philippine military was confident, based on field reports, that Mr Zulkifli and the other named leaders were dead.

Members of Abu Sayaaf, a kidnap-for-ransom group that is responsible for a wave of terrorist attacks in the Philippines, reportedly took away wounded.