Military officials in the Philippines say troops have shot dead one Muslim rebel and wounded an unknown number in the first clash with the guerrillas since two hostages were killed in a rescue operation last week.

Gracia Burnham survived the rescue operation

The officials said four army soldiers were also wounded in the fighting with the Abu Sayyaf rebels on the southern island of Basilan and were later evacuated by US helicopters.

The US - which links the guerrillas to Osama bin Laden's al-Qaeda network - said its troops were not involved in the fighting.

US special forces were sent to the Philippines in February, to help the government in Manila fight against the Abu Sayyaf guerrillas.

Failed rescue

It was the first clash since a local nurse and a US hostage were shot dead last week during an attempt to free them.

Ediborah Yap and Christian missionary Martin Burnham were killed during a gun battle between the guerrillas who had held them for more than a year and Philippines soldiers.

A third hostage, Mr Burnham's wife Gracia, was shot and injured and has since returned to her hometown of Wichita, Kansas.

Philippines media have reported that Ms Yap turned down several chances for freedom during the last year, deciding to stay with the Burnhams who had suffered bouts of bad health.

Most of the Abu Sayyaf kidnappers are still on the run in the jungles of the southern Philippines, where about 1,000 US troops have been helping train local soldiers.

The Abu Sayyaf group, which says it is fighting for a Muslim state, carried out a string of kidnappings last year.

Most hostages were released for ransom, though some, including an American man, were beheaded.