The LTTE said they killed at least 30 government troops in Sunday's five-hour fighting, capturing several gun positions and military detachments.
At Sri Lanka's front line
Al Jazeera's Tony Birtley gets exclusive access to the heart of the conflict in the east of Sri Lanka
Ilanthirayan said the piece of land had been taken by the military in the past few months. "We are holding that place and consolidating our positions," he said.
The defence ministry in Colombo, however, said the military had beaten back an LTTE offensive and killed at least 52 Tamil Tiger fighters.
The contradictory claims – a regular feature of Sri Lanka's civil war – could not be independently verified.
Government troops and LTTE fighters have been engaged in worsening fighting since a 2002 Norwegian-brokered ceasefire collapsed last year.
Japan's embassy in Sri Lanka said that Akashi was planning to "to discuss with the government and the parties concerned the current situation of the peace process and its future".
The Tamil Tigers have been fighting for a separate homeland for the island's minority ethnic Tamils since 1972. At least 60,000 people have been killed in the conflict.