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Indonesia (search) warned that a military offensive in Aceh (search) was only days away after rebels ignored a deadline to lay down their arms, while mediators said Tuesday a last-minute deal was still possible.

More than 6,000 arrived Tuesday at a port on a nearby island in preparation for a possible offensive.

International negotiators said separate talks with the government and the Free Aceh Movement aimed at salvaging a five-month-old peace agreement were continuing in Jakarta (search), Banda Aceh and Stockholm.

Security Minister Bambang Yudhoyono said late Monday that he expected President Megawati Sukarnoputri to issue a decree this week allowing for a security operation in the province. The decree would also allow for beefed up police and the reopening of some closed government offices.

"The president has decided to launch an integrated operation in Aceh and I expect her to issue a decree explaining when the operation will start," Yudhoyono said.

The pact to end the 26-year civil war -- which has killed nearly 12,000 people on the northern tip of Sumatra island, about 1,200 miles northwest of Jakarta -- has appeared to unravel in recent weeks.

A Monday deadline for rebels to accept government demands to lay down their weapons arms and drop an independence bid passed without incident or the rebels disarming. But international peace monitors withdrew to Medan in North Sumatra because of the potential for new fighting.

Meanwhile, negotiators said war could be avoided and called on both sides to "take a step back."

"It's a very small window here and it is closing quickly," said David Gorman, a negotiator with the Geneva-based Henry Dunant Center, which brokered the Dec. 9 peace agreement. "But it's not dead yet."

Army chief Gen. Ryamirzard Ryacudu arrived Monday in Banda Aceh to oversee the replacement an Acehenese military chief with one from Jakarta. Ships carrying more than 6,000 troops docked Tuesday at Tanjung Bintan port on Bintan Island, near Singapore ahead of a possible offensive.

"We are ready. We are waiting for the green light," Aceh military spokesman, Lt. Col. Firdaus Komarno.