BANDA ACEH, Indonesia — Security fears again threatened to hamper tsunami relief efforts Monday, with United Nations officials banning aid workers from travelling in parts of devastated Aceh province following reports that fighting had broken out between Indonesian government forces and insurgents.

The travel ban also came after Denmark warned its aid workers to beware of an imminent terror attack -- a caution that prompted UN officials to launch an investigation and declare a state of "heightened awareness'' in Aceh, where separatists have been fighting for an independent state for decades.

Insisting that aid workers had nothing to fear, rebel leader Tengku Mucksalmina dismissed Indonesian government claims that insurgents might attack relief convoys in hopes of stealing food for their fighters.

"Our mothers, our wives, our children are victims from this tragedy. We would never ambush any convoy with aid for them,'' Mucksalmina told The Associated Press from his jungle hideout outside Banda Aceh. "We want them (aid groups) to stay. We ask them not to leave the Acehnese people who are suffering.''

The travel ban between the provincial capital of Banda Aceh and the east Sumatran city of Medan came "strictly because of the fighting going on down there,'' said Mans Nyberg, a spokesman for the UN High Commissioner for Refugees.

"There was reportedly a small battle between the army'' and the rebels, Nyberg said. He didn't know when the battle occurred.

Joel Boutroue, the head of the UN relief effort in Aceh, said the ban "was not due to any specific threat'' and that it would be reviewed Tuesday.

The death toll in one of the world's worst natural disasters stood Monday at more than 162,000, with thousands of bodies found over the weekend in Sumatra, which was closest to the Dec. 26 9.0-magnitude earthquake that spawned killer waves in 11 countries. Also hard hit were Sri Lanka, India and Thailand.

Six Canadians have been confirmed dead in the disaster and 25 others are officially listed as missing, most of them in Thailand.

On Monday, Prime Minister Paul Martin paid a visit to Canada's Disaster Assistance Response Team, or DART, in Ampara, Sri Lanka, and met in Colombo with Sri Lankan parliamentarians, including three members of the Tamil National Alliance.

The prime minister said he wasn't prepared for the devastation he saw in the Ampara district, and that the degree of destruction and human loss took his breath away.

On Tuesday, a UN conference on natural disasters opened in Kobe, Japan with hundreds of experts and officials from around the world expected to focus on the creation of a tsunami warning system that could prevent catastrophies stemming from tsunamis.

The tsunami has focused new attention on the a warning system for the Indian Ocean similar to one on guard for killer waves in the Pacific.

Relief efforts in Indonesia are being led by nearly 15,000 U.S. troops -- most of whom are docked off the coast of western Sumatra island. Australia, Singapore, Germany and other countries also have contributed troops.

Indonesian Foreign Ministry spokesman Marty Natalegawa declined to say whether the UN precautions were necessary. He said that he could not assess them until he understood the rational for the Danish warning.

But Mucksalmina said the security warnings were part of an ongoing Indonesian government campaign to discourage foreigners from getting involved because it would bring human rights abuses in Aceh to light.

"The Indonesian military is afraid of foreigners,'' the 31-year-old commander said. "They are afraid of greater scrutiny of what's going on in Aceh.''

Mucksalmina said his forces didn't need to raid aid convoys because they had purchased a year's supply of rice, instant noodles and other food before the Dec. 26 tsunami hit.

"We were ready to come down from the mountain to give our supply of food, to help clear up the corpses, to help our people,'' Mucksalmina said in a rare interview inside a wooden shack, guarded by about 15 fighters with M-16 and Kalashnikov rifles.

"But the military operations continued throughout Dec. 26, 27, 28. On the fourth day, I lost two of my men'' in a gunbattle, he said. As he spoke, helicopters continuously buzzed overhead. Some of the rebels ate sticky rice wrapped in banana leaves, and sacks of food and ammunition were piled nearby.

Other governments whose nationals are working in Aceh said they had not upgraded their security warnings in recent days.

Japan's Foreign Ministry said it had no new information to warrant raising its warning for Indonesia. The German Foreign Ministry said it had not raised its terror alert, either.

The two countries are among many that included Indonesia on their list of countries where a terrorist threat exists. Jemaah Islamiyah, an Al-Qaida-linked group, is blamed for a series of deadly bombings in Indonesia in recent years, and other radical groups operate in the country.