Norway said on Thursday it had demanded an immediate explanation from Sri Lanka for a grenade attack against unarmed Nordic truce monitors.
Aid Minister Erik Solheim said the Norwegian-led Sri Lanka Monitoring Mission (SLMM) came under grenade attack in the island's north on Wednesday while examining a route to the Jaffna peninsula.
"It is very worrying that the civilian Sri Lanka Monitoring Mission, headed by Lars Solvberg, came close to being hit by grenades fired by the Sri Lankan army near Pooneryn, in northern Sri Lanka," Solheim said in a statement.
"We have asked the Sri Lankan government for an immediate explanation," he added.
Solheim said he was also concerned by the deteriorating situation in Sri Lanka, where Oslo has been trying to broker peace at the invitation of the government and the Liberation Tigers of Tamil Eelam (LTTE).
"I am very troubled by the government's onslaught in Vakarai, in the eastern part of Sri Lanka," he said, referring to Wednesday's bombing, which killed some 65 civilians.
"Yet again it is civilians who are being killed and made to suffer due to military operations."
Solheim said he was "extremely disappointed" that the parties were not honouring the promises they made in Geneva a week and a half ago to refrain from launching any military offensives and to abide by a 2002 cease-fire agreement.