Retired US general and former CIA chief David Petraeus says the war in the Philippines is “a big concern” for Australia.

Just over five weeks ago, pro-Islamic militants took control of Marawi City, on a southern island of the country, and has since occupied it with as many as 500 fighters.

The Armed Forces of the Philippines have been fighting to dislodge them without success. More than 350 people have died since the fighting broke out.

“This is not a problem that can be resolved in years but in decades, and one where Australia could take the lead,” Petraeus told Fairfax Media.

“A point that political leaders have to communicate is that this is a generational struggle.”

Philippines president Rodriguez Duterte had planned to have the fighting ended by the end of Ramadan but has failed to come through on some of the measures he promised to undertake in order to wipe out the militants, including “carpet bombing” the city.

Petraeus says the war is a result of inconsistent surveillance, by local and international authorities, of terrorism networks.

“Collectively, a lot of us – including the Philippines government, which was concentrating its efforts on counter-narcotics – took our eye off that particular ball. It shows you have to have a sustained commitment.”

Last week the Australian government announced that the RAAF will be flying two P-3 Orion aircrafts over the Philippines to help the country’s military fight the militants.

The planes specialised in advanced intelligence-gathering.

“The regional threat from terrorism, in particular from Daesh [Islamic State] and foreign fighters, is a direct threat to Australia and our interests,” defence minister Marisa Payne said at the time.

The Sydney Morning Herald has more here.

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