COLOMBO, Sri Lanka - Aid groups pushed for access to Sri Lanka's former battlefields to check on any wounded civilians stranded there, as the country celebrated a holiday Wednesday to honor the military's victory over the Tamil Tiger rebels.

Though the president officially declared the country free from terror on Tuesday, government forces shot and killed two squads of rebel fighters -- a total of eight insurgents -- who were preparing ambushes in eastern Sri Lanka, the military said. Pockets of rebel fighters are presumed still active in the east and officials suspect that sleeper cells are hidden in cities across the country as well -- raising fears the war could continue in the form of an insurgency in the country's cities.

Security remained tight around Colombo, which is filled with checkpoints and patrolling troops.

The government has barred journalists and international aid workers from the war zone for months, allowing only the Red Cross to periodically send a boat to the area to deliver food aid and evacuate the wounded.

The Red Cross has appealed for access to the war zone to aid anyone still left there, but the government says it does not need assistance, according to Paul Castella, the head of the Sri Lanka office of the International Committee of the Red Cross.

"Yes, we have concerns; yes, we are asking for access," he said. "We have no information from the ground to document these concerns."

As the military encircled the rebels and pushed ahead with the final battle last week, government doctors reported about 1,000 wounded civilians were trapped in a makeshift hospital -- which has served as the area's only medical facility for more than three months -- and the surrounding area with little food and no medical care.

Military spokesman Brig. Udaya Nanayakkara said troops rescued more than 60,000 civilians caught in the fighting in the final days of the war. He said soldiers found several wounded people when they captured the area, but no one was in the hospital.

"There are no civilians still in that area. All of them have been evacuated," Nanayakkara said.

Castella said 19 local Red Cross workers along with their families were missing.

"These people were together with the population there and taking an active part in the medical evacuations. They have the same fate as the rest of the population," he said. "We don't know where they are and, as you can imagine, we are extremely worried."

U.N. humanitarian chief John Holmes has also called for U.N. officials or the Red Cross to be allowed to go to the former battlefield to confirm that all civilians are out.

The U.N. has said at least 7,000 civilians were killed and 16,000 wounded in the recent fighting. An estimated 265,000 civilians were also displaced and most of them were sent to government-run camps in the north.

Aid groups complained access to those displacement camps has been severely restricted since the weekend.

Aid workers were no longer allowed to speak to the displaced civilians or bring vehicles into the camps, forcing them to carry in huge shipments of aid in by hand, one worker said, speaking on condition of anonymity out of fear of government reprisals for speaking about the restrictions.

"There are problems providing adequate quantities of aid to a population, which is extremely fragile," U.N. spokesman Gordon Weiss said.

Meanwhile, Sri Lankans commemorated the victory over the rebels with a national holiday. The celebrations were relatively subdued Wednesday, after three days of dancing in the streets. Many people cooked pots of milk rice -- a traditional celebratory treat -- in the streets, handing out samples to passers-by.

In the predominantly Sinhalese town of Gampaha, people braved a heavy downpour to wave flags in the streets and to pass out sweets.

"We all lived with fear for decades, we are now free," said Janaka Ranasinghe, who works overseas.

However, there were no street celebrations in Colombo's predominantly Tamil neighborhood of Wellawatte, where many remained indoors.

In his victory speech Tuesday, President Mahinda Rajapaksa reached out to the Tamil minority, calling for political compromise to unify the island nation after the defeat of the rebels and the death of their leader.

But broad distrust between ethnic communities following a quarter century of warfare could make it difficult for Rajapaksa to accomplish that goal.

He also extended a hand to the mainly Hindu Tamil community, which comprises 18 percent of the country's 20 million people and has complained of decades of discrimination at the hands of the mainly Buddhist Sinhalese majority.

"All the people of this country should live in safety without fear and suspicion. All should live with equal rights. That is my aim," he said, briefly speaking in the Tamil language.

Speaking in Geneva, U.N. Secretary-General Ban Ki-moon said Tuesday "the legitimate concerns and aspirations of the Tamil people and other minorities must be fully addressed."

He said he would travel to Sri Lanka on Friday and hoped to visit camps for the thousands of people uprooted by the war.

Finding a resolution to the years of conflict is expected to hinge on the devolution of power from the central government to the provinces, which would give Tamils a significant say in the north and east, where they have large populations.

But Rajapaksa faces significant hurdles in trying to forge a political compromise between the Tamils and Sinhalese nationalists.