Sri Lanka's government said it pushed Tamil Tiger rebels from the mouth of strategic Trincomalee harbour in the island's restive north-east on Monday, and that it would therefore halt its offensive.
The military recaptured the southern edge of the harbour after days of artillery battles for control of the area called Sampur - the first major capture of enemy territory by either side since a 2002 cease-fire.
The rebels had been able to shell a major naval base and disrupt a maritime supply route to the besieged army-held Jaffna peninsula to the north from their positions in Sampur.
"We are in total control," said Keheliya Rambukwella, a government defence spokesman and minister for policy planning. "Thereafter, we will not continue with any offensive operations unless we are forced to as a result of enemy action."
He said the entire harbour mouth, which had included several Sea Tiger bases, was now in government hands.
The Tigers said they were still fighting troops with mortar bombs and small arms fire in Sampur's suburbs, and accused the government of trying to destroy what is left of the truce - which still technically holds on paper.
"This is a severe breach of the cease-fire agreement with the Sri Lankan military taking LTTE-controlled areas," S. Puleedevan, head of the rebels' peace secretariat, said by telephone from the Tigers' northern stronghold of Kilinochchi.
"They are not honouring the cease-fire agreement. They are forcing it to the brink of collapse," he added. "On our side we are fully committed to it."
Analysts fear the Tigers might launch attacks elsewhere in retaliation.
Hundreds of troops, rebels and civilians have been killed and more than 200,000 people displaced during more than a month of renewed civil war.
By Sunday, at least 14 soldiers had been killed and 92 wounded since the Sampur offensive began a week earlier. The army estimates around 120 rebels were killed there by the weekend.
There were no details of any new casualties during Monday's advance. Analysts said the Tigers appeared to have pulled out of Sampur, a tiny settlement of a handful of rough houses and shops, a Sea Tiger memorial and an LTTE political office. Most of the civilian population had already fled south.