When rebels met Norway's peace envoy in their nothern stronghold on Tuesday, they discussed tsunami aid and not the long-stalled peace talks, an impasse that officials say needs addressing fast.
"It's a vacuum, because the ceasefire (has) only temporary status, and there is a need to at least start the peace talks," Nordic monitoring mission head Hagrup Haukland said on Tuesday - the third anniversary of the ceasefire between the two sides.
"There is deep suspicion still."
Peace talks have been suspended for nearly two years as the two sides squabble over demands by the Liberation Tigers of Tamil Eelam (LTTE) for interim self-rule in the north and east.
"The killings are the most serious threat to the ceasefire because they create frustration, uncertainty," Haukland added. "There are elements which do not want peace ... and want to provoke a situation in which one of the parties will say 'enough is enough, now we go back to war'."
When the Tigers' eastern political wing leader E Kousalyan was slain in early February along with four other rebel cadres in the most high profile assassination since the truce was signed in 2002, Haukland said he worried that war was inevitable.
"We have been thinking many, many times that the ceasefire now is over"
Nordic monitoring mission head
"We have been thinking many, many times that the ceasefire now is over," he said.
The fatal ambush of Kousalyan was the latest in dozens of killings of rebels and their foes in the restive east in a silent war between the Tigers and a breakaway faction led by Karuna, a renegade commander they accuse the military of aiding.
Antagonism between the government and rebels reached fever pitch late last year, when the Tigers threatened to resume their struggle if their self-rule demand was not discussed soon.
Asia's tsunami came as a sudden tension-breaker as both sides turned to safeguard and rebuild ravaged coastal communities, and raised hopes of new era of cooperation - which the killings then promptly erased.