Bangkok: Australia has warned of a "high threat" of terror attack in the Philippines, including in the capital Manila.
Australia's smartraveller.gov.au warns Australians "to be alert to possible threats around locations that have a low level of protective security and places known to be possible terrorist targets".
It also tells Australians to reconsider travel to eastern Mindanao and avoid the island's central and western regions, which include Marawi where about 30 Islamic State-allied militants are still hiding out in building basements and tunnels amid the city's ruins.
Philippine security officials have also warned of possible "lone wolf attacks".
Four militants were killed in skirmishes with government in Marawi over the past several days, including an Indonesian. The presence of armed militants supporting IS is posing a threat to 400,000 residents who want to return to the lakeside city.
"The main battle area, where most of the heavy fighting occurred in the last few weeks prior to the liberation and cessation of combat operation still harbours a number of stragglers," military spokesman Major-General Restituto Padilla told reporters. Marawi had been declared liberated on October 23.
Australia's warning comes as Philippine security forces prepare a massive security blanket to protect world leaders attending meetings in Manila and the nearby Clark International Airport and development zone in mid-November.
Prime Minister Malcolm Turnbull and US President Donald Trump are scheduled to be among the leaders attending an Association of Southeast Asian Nations (ASEAN) summit and related meetings.
More than 60,000 soldiers and police will be deployed to protect the leaders and officials. The movement of ships will be restricted on Manila Bay and a gun ban will be enforced across Manila and surrounding areas.
Philippine officials say President Rodrigo Duterte, who will host the meetings, will call for greater cooperation to crush violent extremism in the region.
More than 1100 people, including about 900 militants, have been killed in Marawi, the Philippines' largest Islamic city, since fighters waving Islamic State flags took it after rampaging through the streets on May 23.
Major-General Padilla denied the announcement of the city's liberation was premature.
"Those stragglers who were left, they are leaderless, they have no direction," he said.
"They are merely fighting for survival so they have no impact on the overall security of the place."
Australia and the Philippines have boosted military ties in response to the increasing threat from terror organisations in the Philippines, including increasing intelligence sharing and Australian soldiers training their counterparts in urban warfare.