The British Foreign Office upgraded a travel warning to cover a Muslim-dominated eastern area of Sri Lanka, as daily fighting between government forces and Tamil Tiger rebels continued to make the country unsafe.
In overnight violence, a Tamil Tiger rebel was killed in a gunbattle in the volatile northern Jaffna Peninsula, the military said on Saturday.
It also accused separatists of murdering a civilian woman Friday in the eastern town of Batticaloa.
The rebels were not immediately available to comment on the incidents.
A statement posted on the Foreign Office's Web site Friday advised against travel to Ampara town and Arugam Bay due to "the continued deterioration of the security situation," after the massacre of 10 Muslims in the area sparked violent riots earlier in the week.
On Monday, the bodies of 10 Muslim labourers were found in a remote jungle in Muslim-dominated Pottuvil, an area about 250 kms east of the capital, Colombo.
Muslim protesters took to the streets of Pottuvil on Wednesday, claiming an elite police force was responsible for the slayings.
Police, who denied the allegations, fired on the protesters, wounding 14, then imposed a temporary curfew.
British authorities have been advising against travelling to the north and east of Sri Lanka since renewed fighting between government troops and ethnic Tamil Tiger rebels broke out in August.
More than 1,000 combatants and civilians have been killed in the resurgent violence.
The Tamil rebels began fighting in 1983 for a separate homeland in the north and east for Sri Lanka's largest ethnic minority.
The conflict was nominally halted by a Norway-brokered ceasefire in 2002 although the recent wave of violence has threatened to drag the country back into full-scale civil war.
Norwegian Ambassador Hans Brattskar on Friday met the Tamil Tigers' political leader, Suppiah Thamilselvan, in the northern rebel stronghold Kilinochchi.
The two discussed a recent rash of abductions, the rebels said on their official website. No additional details were available.
Hundreds of civilians have been killed or have disappeared in shadowy circumstances since December, when the latest surge of fighting began in earnest.