Joanne Collins, Jakarta – Seven navy vessels carrying some 3,000 marines sailed for troubled Aceh on Thursday, even as officials said there was time to talk with rebels and that the government would consult parliament on plans for the province.

The troops set sail for resource-rich Aceh on the northern tip of Sumatra island from the East Java city of Surabaya, where Indonesia's military chief told troops to brace for war.

General Endriartono Sutarto said Thursday there would be no halfway measures in any attack if Free Aceh Movement (GAM) rebels refuse to lay down their arms in the resource-rich province. "If then the government decides to solve Aceh through a military operation, then yes, we need to be all out because it will be the last way for the government to solve problems in Aceh. We cannot be fifty-fifty," Sutarto said.

But Foreign Minister Hassan Wirajuda said time remained for GAM to accept Jakarta's terms for peace talks, which include abandoning their independence goal and laying down their arms. "May 12 is still ahead. Thus, at this second, I would not say that resolution has failed," Wirajuda told reporters. The government has set a May 12 deadline for talks with GAM.

In a hint major military action could come later rather than sooner, chief security minister Susilo Bambang Yudhoyono said the government would consult parliament about what it planned to do in Aceh after the May 12 deadline had passed. "The government plans to brief parliament in a consultative meeting after May 12 to explain its steps," he told reporters.

In a statement issued on Thursday, GAM military spokesman Sofyan Daud said all GAM troops had been ordered "to report as soon as possible to their posts". "We wait to see what the Indonesian government will do on May 12 and the days ahead," the statement said.

It also warned several major companies operating in Aceh, including Exxon Mobil, that they were considered military targets and should halt their activities "within 24 hours after the Indonesian government announces its war".

Any full-scale attack on GAM would effectively end a December peace deal aimed at halting a decades-long conflict that has killed at least 10,000 people, most of them civilians. Military sources say that before April 25, Indonesia had 26,000 troops in Aceh. Some 6,000 additional soldiers have already arrived or are on the way and another 3,350 are due to go, which would take the total to about 36,000. The number of police in the province is unclear but authorities are preparing to send an additional 12,000 if the peace deal falls through.

Jakarta has been seeking immediate peace talks inside Indonesia with GAM after a dispute over timing last month led to an eleventh-hour cancellation of a meeting in Geneva. GAM has so far rejected Jakarta's demands and also said any meeting would have to come after May 12.

Renewal of the conflict in Aceh would be bad publicity for Jakarta, struggling to lure investors after years of economic turmoil and damage to its image from October's Bali bombings, blamed on Islamic militants, that killed more than 200 people.

[With reporting by Telly Nathalia.]