"We have made some very good catches in the ongoing military crackdown although we cannot divulge details of the operations at this stage," Assam Chief Minister Tarun Gogoi told journalists here, 490 km east of Guwahati, the state capital.

At least 20,000 army, police, and paramilitary troopers are currently engaged in a massive offensive against the outlawed United Liberation Front of Asom (ULFA), blamed for a recent wave of attacks on Hindi-speaking migrant workers in Assam.

Four days of violence between Jan 5 and 8 had left 73 people dead, 61 of them migrant workers from Bihar, five policemen and two government officials killed in a landmine explosion, and five ULFA militants killed by security forces in separate encounters.

"We have got some vital information from the captured militants and efforts are on to track down ULFA rebels that could be hiding in the jungles," the chief minister said.

An army commander said at least a dozen ULFA guerrillas were captured since the operations began Jan 8.

Thousands of soldiers scoured thick jungles in Assam and the adjoining state of Arunachal Pradesh to hunt for the rebels.

"Some of the militants might have crossed over to Myanmar where they have bases," Gogoi said. He said despite the security offensive, the government was ready to hold peace talks with the ULFA, a rebel group fighting for an independent homeland since 1979.

"Our doors for talks are still open and the security operation would stop the moment the ULFA agrees to shun violence," Gogoi said.

Indian Prime Minister Manmohan Singh is arriving in Assam Tuesday on a daylong visit to review the military offensive, besides meeting family members of those killed in the recent violence.

"The prime minister's visit is aimed at reassuring the people and instilling a sense of confidence among the Hindi-speaking migrant workers," the chief minister said.

Manmohan Singh is scheduled to visit village Masaldhari Chapori in the eastern Tinsukia district - the scene of a bloody massacre where 13 migrant workers were killed by the ULFA. He would also visit Sepon in the adjoining Dibrugarh district and meet hundreds of migrant workers sheltered in government-run camps as a precautionary measure.