British Prime Minister David Cameron arrived Thursday in Sri Lanka ahead of a Commonwealth summit which is set to be overshadowed by his historic visit to the island's former war zone.

Cameron flew in to Colombo around midnight (1830 GMT) from neighboring India on the eve of the summit, according to a photographer at the airport.

Britain will send the helicopter carrier HMS Illustrious to the Philippines to help with relief efforts after Super Typhoon Haiyan, Prime Minister David Cameron said Thursday.

"I can announce Britain is sending the carrier HMS Illustrious to help with #TyphoonHaiyan," Cameron, who is heading to a Commonwealth summit in Sri Lanka, said on his official Twitter account.

Sri Lankan President Mahinda Rajapakse said Thursday that he was ready to defend his country against allegations of war crimes at this week's Commonwealth summit, saying it had "nothing to hide".

"We are very open, we have nothing to hide," Rajapakse told reporters on the eve of the 53-member group's summit, which is set to be dominated by allegations of abuses during the final stages of Sri Lanka's 37-year ethnic conflict.

India has yet to decide whether Prime Minister Manmohan Singh will attend a Commonwealth summit in Sri Lanka amid mounting pressure on him to boycott the event, a foreign ministry official said Saturday.

The spokesman's statement came amid widespread Indian media reports that Singh would skip next week's meeting in Colombo.

Prime Minister David Cameron has promised Britain's Tamil community he will push for an international probe into alleged war crimes and human rights abuses when he attends a Commonwealth summit in Sri Lanka.

Cameron held talks with critics of President Mahinda Rajapaksa's rule to explain his decision to attend the meeting in Colombo on November 15-17 despite calls for a boycott.

Britain's David Cameron will become the first foreign leader to visit Sri Lanka's war-torn Tamil heartland during next month's Commonwealth summit when he will press Colombo on human rights.

The British premier is under pressure at home and abroad to boycott the summit over the bloody end to Sri Lanka's ethnic conflict but he vowed in a meeting with Nobel laureate Aung San Suu Kyi to have some "very tough conversations" with President Mahinda Rajapakse's government.

Canada's Prime Minister Stephen Harper said Monday he will boycott a summit of Commonwealth nations next month, citing serious rights abuses that he says remain unaddressed by host nation Sri Lanka.

"Canada is deeply concerned about the situation in Sri Lanka," Harper said in a statement formally announcing his decision to send a lower-ranking official to represent Ottawa at the November 15-17 summit of nations with ties to the former British Empire.

The United Nations' rights chief Navi Pillay, who is investigating allegations of war crimes by Sri Lanka, is the target of a smear campaign by Colombo, her office said Friday.

Pillay's spokesman Rupert Colville said there had been no letup in the "extraordinary array of distortion and abuse" the U.N. high commissioner for human rights faced from Sri Lankan officials during a fact-finding mission there last month.

Police in Sri Lanka have discovered 100 kilos (220 pounds) of TNT on a truck impounded at a Colombo police station for the past 17 years, officials said Friday.

The vehicle had been seized in February 1996, during the country's civil war, less than two weeks after a truck bomb hit the Central Bank building in Colombo, killing 91 people and wounding 1,200 others.

The U.N. rights chief Monday raised fresh concerns for the safety of Sri Lankan journalists and activists she said had been harassed by the authorities for meeting with her.

Navi Pillay told the U.N. Human Rights Council in Geneva she was worried about those she met during her week-long visit to the island, which is emerging from decades of ethnic war.