The Sri Lankan Navy says it has sunk a boat belonging to the rebel Tamil Tiger group after the rebels opened fire. The incident is the latest blow to a 2002 cease-fire between the government and the rebels, which is in danger of collapsing and returning the country to civil war.
Officials say two boats belonging to the Tamil Tigers began Friday to fire at Navy patrol boats, which promptly returned the fire. One of the boats of the rebels' so-called "Sea Tigers" unit then exploded.
Officials say the size of the blast suggests that the boat had been packed with explosives, and may have been intended as a suicide vessel. The rebels have been known to use such devices before.
Officials also say the Sri Lankan Air Force was called to the area, off the northwestern district of Mannar, but it is not clear whether warplanes became involved in the exchange. The sinking of the Sea Tigers' boat could not be independently confirmed.
The incident Friday is the latest in a series of deadly clashes that threaten to destroy the 2002 cease-fire signed between the government and the Tamil rebels.
Norway brokered that agreement, and has mediated during the subsequent four years of intermittent peace talks between the two sides. Most recently, Norway garnered an agreement from each side to meet for talks in Geneva, Switzerland, in April.
But that meeting was called off when the two sides failed to agree on preliminary matters.
Jehan Perera is with the advocacy group, the National Peace Council of Sri Lanka. Despite the latest violence, he says both the government and the rebels still consider the ceasefire valid.
"Both parties are saying, are claiming, that they uphold the ceasefire agreement, and both parties are engaged in the preliminaries before resuming peace talks in Geneva," said Perera. "So these are the two reasons why we say that there is still a peace process going on, even though on the ground there is so much violations taking place."
The Tamil Tigers have waged a more than two-decade-long campaign for greater rights for Sri Lanka's ethnic Tamil minority. At first, the rebels demanded independence for predominantly Tamil areas of the country in the North and East. Later, they said they would settle for greater autonomy in those areas. More than 60,000 have died in the conflict.
On Saturday, Japanese peace broker Yasushi Akashi is expected in Sri Lanka, for a four-day visit that is to include meetings with President Mahinda Rajapakse and, separately, rebel leaders.
Perera says the Japanese envoy may have a greater impact than Norwegian delegations that have visited recently, because Japan is Sri Lanka's largest aid donor.
"The Norwegians seem to lack the muscle to put pressure on the two sides," Perera said. "Perhaps Japan, as the largest aid donor to Sri Lanka, has economic muscle in the sense that the Sri Lankan government needs the money that the Japanese government gives."
Perera says the rebels would also be open to Akashi's visit, because of the possibility of future development aid for Tamil areas.
Friday's incident is not the only clash to threaten the cease-fire. Last month, a woman suicide bomber blew herself up at the army headquarters in the capital, Colombo, killing seven people. The government responded with two days of air strikes in rebel-held territory.