Banda Aceh, Indonesia ? Foreign aid workers in Indonesia’s tsunami-stricken Aceh province must take military escorts to areas facing insurgency violence, the government announced early today, the latest in a series of security demands that also require U.S. and other foreign troops providing relief to leave the country by the end of March.

The government’s moves, which include an order that aid workers declare their travel plans or face expulsion, highlight its sensitivities over foreign military involvement in a humanitarian effort and underscore its efforts to regain control of Aceh province, the scene of a decades-old conflict between separatist rebels and federal troops accused of human rights abuses.

The United Nations expressed concern that the new demands could create bottlenecks in aid deliveries.

Indonesian military spokesman Col. Ahmad Yani Basuki said in a telephone interview that the army considered only the areas around the provincial capital Banda Aceh and the stricken coastal town of Meulaboh safe for foreigners.

“Other areas aside from that are potential trouble spots,” he said. Anyone going to the troubled zones must take military escorts. But Basuki warned: “We don’t have enough personnel to secure everyone.”

The latest restrictions placed on the international presence came as the aircraft carrier leading the U.S. military’s tsunami relief effort steamed out of Indonesian waters Wednesday after the government declined to let the ship’s fighter pilots use its airspace for training missions. The USS Abraham Lincoln’s diversion was not expected to affect aid flights, however.

U.S. Marines have also scaled back their plans to send hundreds of troops ashore to build roads and clear rubble. The two sides reached a compromise in which the Americans agreed not to set up a base camp on Indonesia or carry weapons.

Instead, the Marines, some 2,000 of whom were diverted to tsunami relief from duty in Iraq, will keep a “minimal footprint” in the country, with most returning to ships at night, said Col. Tom Greenwood, commander of the 15th Marine Expeditionary Unit.

In Washington, the White House asked the Indonesian government to explain why it was demanding that the U.S. military and other foreign troops providing disaster relief leave the country by March 31.

“We’ve seen the reports. … We’ll seek further clarification from Indonesia about what this means,” said Scott McClellan, press secretary to President Bush. “We hope that the government of Indonesia and the military in Indonesia will continue the strong support they have provided to the international relief efforts so far.”

In announcing the decision, Indonesian Vice President Jusuf Kalla said Tuesday that “a three-month period is enough, even sooner the better.”