The United Liberation Front of Asom wants four of its top leaders released from jails before it can respond to the Centre's invitation for talks.

The The Assam Tribune newspaper on Tuesday quoted ULFA commander-in-chief Paresh Baruah as saying, "All 10 members of our central committee will have to be present to discuss the Centre's latest offer."

Baruah spoke to the newspaper from an undisclosed location. He said only six of the committee members are 'free' and the rest, in jails in India and Bangladesh, will have to be freed to discuss the offer.

Baruah was talking in the context of an invitation sent by National Security Adviser M K Narayanan under instructions from Prime Minister Manmohan Singh [Images] through ULFA emissary and Assamese writer Indira Goswami.

• ULFA ready for talks with Centre

The letter from the Prime Minister's Office is in response to a letter from the ULFA chairman to the prime minister two months ago in which the group offered to hold talks if New Delhi discussed its main demand for sovereignty or independence.

The Centre is not willing to accept sovereignty in its agenda.

"We are hopeful of a breakthrough. We are ready to extend whatever is required to facilitate negotiations with ULFA," Assam Chief Minister Tarun Gogoi said.

• Top ULFA leaders surrender

Last Wednesday, Indian home ministry and Assam government officials signed a ceasefire pact with the National Democratic Front of Bodoland in New Delhi, another powerful tribal rebel group in Assam.

"If ULFA joins the peace process like the NDFB, we hope to bring the curtains down on one of the most violent insurgencies in the northeast," Gogoi said.

Over the last two days, ULFA triggered a series of explosions targeting power transformers and road bridges, besides attacking an army convoy and injuring four soldiers.

ULFA is among militant organisations in the northeast that has spurned proposals for negotiations, which would have paved the way for a ceasefire on the lines of the National Socialist Council of Nagalim or the Dima Halam Daoga.