Sri Lanka's Foreign Minister has been shot and killed by an unidentified gunman in the capital, Colombo. 

Officials say Lakshman Kadirgamar was shot by a sniper while leaving his swimming pool to enter his house in a tightly guarded compound in Colombo late Friday. He was rushed to the hospital, but died of his injuries shortly thereafter.

[Sri Lankan President Chandrika Kumaratunga declared a state of emergency following the assassination.]

No one has claimed responsibility for the assassination, and senior government officials have yet to assign any blame. But a senior police official has speculated that the shooting was the work of the Tamil Tiger guerrilla group.

The assassination comes amid growing tension between the rebels and the government, who signed a ceasefire agreement in 2002.  Recently however, that agreement has begun to unravel, with tit-for-tat killings between government forces and the rebels taking place in the restive eastern part of the country.

Mr. Kadirgamar is the most senior official to be targeted in recent months.

The Tamil Tigers accuse the government of supporting a breakaway faction of the rebel group, also active in the east of the country. On Thursday, the rebels repeated a warning that the peace plan was nearing collapse and there could be a return to all out war.

A close adviser to President Chandrika Kumaratunga, Mr. Kadirgamar was an ethnic Tamil, who helped guide the president through efforts to forge peace with the rebels.  But both officials have been known for their hardline stance against the rebels, whom they fear want to use the peace plan to buy time before resuming their push for independence. 

The Tamil Tigers waged a bloody two-decade struggle first for independence, and later for greater autonomy in parts of Sri Lanka where ethnic Tamils are in the majority.  More than 60,000 people died in the conflict.

Human rights officials and peace advocates had hoped the two sides would come together in the wake of the Indian Ocean tsunami in December that killed more than 30,000 in Sri Lanka.  But little progress has been made in the peace plan since then.