Truce monitors on Wednesday accused Liberation Tigers of Tamil Eelam rebels of failing to abide by their rulings and denying access to them to carry out independent investigations.
The Norwegian-led Sri Lanka Monitoring Mission made the allegations as its chief Triggve Teleffsen held talks with the LTTE naval chief Soosai on Wednesday.
The talks were held in the northern rebel-held town of Kilinochchi, 330 km north of Colombo. Teleffsen is in the area since Monday holding talks with key Tiger leaders.
Details of the talks were not immediately available.
SLMM deputy chief of mission Hagrup Haukland said the LTTE was in breach of the ceasefire agreement by denying them access to certain areas as well as by building a new camp in a government-held area of the island's northeast.
"During the last two months we have been denied access by the LTTE to certain areas," Haukland said. "Freedom on movement is crucial for us to conduct our investigations."
He said the LTTE behaviour was unacceptable to them.
Haukland said the Tigers must also dismantle a new camp established in the district of Trincomalee.
"Our stand is that the LTTE must dismantle the camp because as we have already ruled that they are violating the ceasefire," Haukland said.