A Sri Lankan ruling party politician and three accomplices were Friday sentenced to 20 years in jai for murdering a British holidaymaker on Christmas Eve and raping his Russian partner.

Sri Lanka announced Thursday an investigation into its military over allegations of rights abuses, following intense international pressure for a war-crimes probe into the island's decades-long ethnic conflict.

President Mahinda Rajapakse said a current government-appointed Commission of Inquiry (COI) would be expanded to probe the military and Tamil rebels over abuses allegedly committed during their war that ended in 2009. 

Sri Lanka's most senior Muslim politician Friday warned that his government's failure to restrain Buddhist monks accused of sparking religious hate attacks will foment Islamic extremism and threaten security.

Justice Minister Rauf Hakeem said he had been under intense pressure from supporters to quit President Mahinda Rajapakse's coalition after it failed to prevent last month's deadly religious violence.

Australia's immigration minister reacted angrily Wednesday to claims by Sri Lankan migrants that they were abused and mistreated by Australian officials while being forced to return home in a controversial mid-sea operation.

Scott Morrison also said he did not think the group of 41 Sri Lankans would suffer mistreatment back home as a result of attempting the trip to Australia.

Australian government lawyers said Tuesday 153 Sri Lankan asylum-seekers were in custody on the high seas and agreed to give three days' notice before handing any back to Colombo, as criticism mounted.

A late-night interim injunction Monday temporarily halted the transfer of the would-be refugees from the boat, whose very existence Canberra had previously refused to confirm.

A High Court on Monday barred Australia from handing back a boat carrying 153 asylum-seekers to Sri Lanka, a day after Canberra returned another vessel to Colombo following a week of secrecy.

The interim injunction from a late-night sitting applies at least until a hearing resumes on Tuesday afternoon and was granted after lawyers argued the transfer was illegal.

Malaysian police on Friday said they have arrested four more suspected Tamil Tiger separatists, including a man allegedly involved in the attempted assassination of a former Sri Lankan president.

The arrests come after three Sri Lankans, including two refugees, were deported in May amid a crackdown on suspected militants, prompting criticism from the United Nations refugee agency.

The U.N. expressed "profound concern" Thursday over reports that Australia was screening Sri Lankan asylum-seekers at sea and handing them over to Colombo, as Prime Minister Tony Abbott denied breaking international law.

Concern has been mounting over the fate of two boats, one reportedly carrying 153 Tamil Sri Lankan asylum-seekers and another with 50 on board, intercepted in recent days by the Australian navy in Australian waters.

Sri Lanka's police arrested key suspects involved in fueling religious riots and looting, an official said Saturday as minority Muslims expressed fears of more unrest ahead of Ramadan.

Police said a total of eight people directly linked to the June 15 anti-Muslim riots were arrested this week and recovered gems and jewelry looted from two shops that were targeted during the violence.

Sri Lanka's media showed rare unity in condemning police Sunday for their failure to control anti-Muslim Buddhist extremists as religious tensions grow in the wake of riots in the island's south.

A day after a Muslim-owned shop was burnt down outside the capital Colombo, the privately-run The Nation weekly took the unusual step of publishing its editorial as the main story on its front page, with the blunt headline: "The IGP (Inspector-General of Police) must resign".