A suspected Tamil Tiger rebel who pretended to be a war refugee blew herself up Monday as Sri Lankan soldiers frisked her at a checkpoint. Twenty troops and eight civilians died.

State TV showed the carnage after the suicide bombing in Vishwamadu, a northeastern town where hundreds of civilians had been waiting to be sent to refugee camps. A woman in a blue dress was curled up in the fetal position, her face and neck spattered with blood; plastic lawn chairs were upended and piled in a jumble from the force of the blast.

A soldier briskly picked up a dead child who was sprawled face down in the dirt, yellow shorts peeping out from beneath her bloodstained pink-and-purple dress. He dropped her rag-doll body on top of another corpse in a truck, leaving their bloodied, bare feet jutting out the back.

The footage, released by the government, did not show the bodies of any soldiers.

Government troops claim to be closing in on the Tamil Tiger rebels in their push to end a 25-year-old war that has killed some 70,000 people. The military has backed the rebels into a strip of land on the northeastern coast, and the Red Cross says some 250,000 civilians are trapped there too.

The suicide attack Monday fed fears that the rebels could be stepping up guerrilla warfare in their battle for a separate state for the Tamil minority. The Tamil Tigers, blamed in more than 200 suicide attacks since 1983, are listed as a terror group by the U.S. and the European Union.

The bomber had concealed herself among more than 800 civilians who had crossed the front lines from rebel-held territory and were being searched by soldiers before being sent to camps further south, military spokesman Brig. Udaya Nanayakkara said. He blamed the Tamil Tigers for the blast, which also wounded 24 troops and 40 civilians.

It was not possible to confirm the details of the attack. Independent journalists are barred from the war zone and most independent aid workers have fled the fighting. The rebels could not be reached for comment late Monday because communications to the north have largely been severed.

The United States and United Nations condemned the bombing.

"We deplore the loss of civilian life in this targeted killing. It's a blow for people who have suffered so much," U.N. resident coordinator Neil Buhne said in Colombo, the capital.

The U.S. Embassy called on the rebels "to allow all civilians freedom of movement" and urged the government to ensure that all civilians who flee the fighting are transferred to the camps "in accordance with international standards."

Monday's suicide attack showed the rebels have no consideration for civilians, Disaster Management Minister Mahinda Samarasinghe said, adding that more than 20,000 civilians have fled the shrinking area held by the rebels in recent days.

Nobel Peace laureate Jose Ramos-Horta, the president of East Timor, urged both sides to agree to a cease-fire to allow aid groups and journalists full access to the conflict zone, and to begin talks to seek a political solution.

Independent U.N. experts in Geneva criticized the "deteriorating human rights situation" in Sri Lanka.

"A climate of fear and intimidation reigns over those defending human rights, especially over journalists and lawyers," Margaret Sekaggya, a U.N.-appointed independent human rights expert, said in a statement Monday.

Last week, Defense Secretary Gotabhaya Rajapaksa accused the BBC, CNN, and Al-Jazeera TV networks of favoring the Tamil rebels and warned they might be banned from the country.

The BBC said Monday it was suspending FM radio programming to the Sri Lanka Broadcasting Corp. starting Tuesday because of what it called "deliberate interference" in its broadcasts.

Sri Lanka Broadcasting chairman Hudson Samarasinghe said the station was not concerned.

"Let them suspend if they want," he said. "We are fighting against ruthless terrorists and we can't allow foreign media to carry biased news."

Meanwhile, in Colombo, hundreds of thousands of Sri Lankans flocked to a patriotic exhibition displaying weapons, boats and even submarines captured from the rebels, underscoring growing optimism that decades of war could be drawing to a close.

"The capturing of these huge vessels and weapons confirms that the end of the Tiger terrorists is very close," Susantha Kumara, 35, said as he ran his hand over the side of a submarine.