A state of emergency has been declared in Sri Lanka after the assassination last night of the country’s foreign minister. A massive operation is underway in the capital Colombo to find the gunmen. Lakshman Kadirgamar, one of the most highly protected members of government, was gunned down in an ambush outside his home.A Tamil himself, Kadirgamar was nevertheless a fierce opponent of the Tamil Tiger rebels fighting for independence in the east of the island. Although no one has claimed responsibility for the attack, police chiefs say they believe the Tigers may have carried out the killing. The incident came a day after the militants warned the government its refusal to hunt down and disarm a Tamil splinter group could rekindle a war that has already claimed more than 64,000 lives.