Sri Lanka's military stopped scores of ethnic Tamils protesters from entering the capital Wednesday ahead of a Commonwealth summit as a British TV crew was barred from a former warzone.
Sri Lanka had hoped the three-day Commonwealth summit, due to start Friday, would showcase its post-war revival after security forces crushed the decades-long Tamil separatist conflict in 2009.
But it is turning into a major public relations disaster as some of the Commonwealth bloc's 53 members and rights groups focus attention on the island's human rights record.
The government also ordered Britain's Channel 4 TV crew not to travel to the former conflict area of Vavuniya after pro-government activists staged a protest and prevented their train from leaving north-central Anuradhapura town.
Callum Macrae, director of Channel 4's award-winning documentary: "No Fire Zone: Sri Lanka Killing Fields", said police told them to return to Colombo.
Media Minister Keheliya Rambukwella said the TV crew were asked to turn back for their own safety.
Visiting British Foreign Secretary William Hague said he raised the issue with his Sri Lankan counterpart, Gamini Lakshman Peiris, during ministerial talks ahead of the Colombo Commonwealth summit.
"We (Britain) are much disturbed," Hague said at the British High Commission (embassy). "Free access is very important, to go anywhere they wish."
"It is natural for any country hosting an international event to come under focus. We believe in freedom of expression and expect them to uphold it," Hague said.
In another development, hundreds of pro-government activists blocked opposition leader Ranil Wickremesinghe from entering his party headquarters where members and guests discussed Sri Lanka's human rights record ahead of the summit.
"Protesters tried to pull the opposition leader from his car but his driver managed to lock the doors and take him to safety," his spokesman Saman Athaudahetti told AFP. "They attacked the car with bare hands."
The Commonwealth Heads of Government Meeting (CHOGM) was hit by a new pullout Tuesday as the prime minister of Mauritius joined those of India and Canada in boycotting the event.
British Premier David Cameron has also been under pressure to boycott the event, but he has promised to hold "tough conversations" with President Mahinda Rajapakse about "accountability" issues.
Meanwhile, ethnic Tamils in the former warzone in the island's north, who were travelling to Colombo for the same opposition- organised rights event, were stopped first by police and later by the military, Roman Catholic priest Emmanuel Sebamali told AFP.
"We've been forced to turn back," the priest told AFP by phone from Vavuniya town, 256 kilometres (160 miles) north of Colombo. "They've refused to give us a reason. They just won't allow us to travel to Colombo."
Sebamali said the 200 Tamils were en route to a meeting to draw attention to thousands who lost loved ones in the bloody conflict.
The final government offensive has been dogged by war crimes allegations, with Sri Lankan troops accused of murdering surrendering rebels and shelling hospitals. Colombo denies any wrongdoing.
Minister Rambukwella said Tamils were not allowed to enter Colombo due to intelligence reports suggesting their presence could breach the peace.
On Tuesday, hundreds of Tamils began a separate protest in Jaffna, pressing authorities to return military-occupied land.
The organiser, Sugirthan Somasundaram, said cow heads were thrown into his home and of another organiser Sunday, along with a note warning them to abandon their demonstration.
They vowed to keep up the protest until Cameron visits Jaffna during his trip.
A UN panel in 2011 found as many as 40,000 civilians may have been killed in the final months of the civil war, mostly due to Sri Lankan military action. But Colombo denies its troops killed any civilians.