Congress president Sonia Gandhi will start her party's campaign for the upcoming Assembly polls in three states by addressing rallies in Manipur on February 5, while Prime Minister Manmohan Singh will campaign in Punjab next week.

Sonia chose Manipur as her first destination amid reports that Congress candidates were being threatened by banned militant groups to either stay out of the poll process or cough up money.

The United Progressive Alliance chairperson will visit the state again on February 11 to address a rally in Imphal, and sources said the state's ruling Congress is hoping that some announcement will be made on the Armed Forces (Special Powers) Act, whose repeal has been demanded by the people.

Militant groups like the PLA, UNLF, KYKL and KCP have been threatening politicians, especially Congress candidates.

The polls to the 60-member Assembly will be held in three phases on February 8, 14 and 23. There is a pressure group in the Congress which has been working to take the prime minister to this north-eastern state, but security agencies are not in favour of such a move, the sources said.

On February 7 and 10, Sonia will visit Punjab, where she will address rallies at various places. The elections to Punjab's 117-member Assembly will be held on February 13. The prime minister will visit Punjab on February 5 and 6 with a night halt at Chandigarh, the sources said.

Ahead of elections to the 70-member Assembly of Uttarakhand, Sonia will address rallies at various places on February 8.

She is expected to visit the state a second time on either February 16 or 17, the sources said.

The prime minister will visit the state on February 13. Elections in Uttarakhand will be held on February 21.

Elaborate security arrangements have been made in the three poll-bound states, with all precautionary measures been put in place well in time, especially in the light of an intelligence input that militants were planning to target VIPs with explosive-laden "toy planes".

The states have been asked to ensure various layers of security in the "funnel" area of airports, proper securing of helipads, and round-the-clock vigil at the venue of poll campaign meetings and places where VIPs would stay, informed sources said.

According to an intercept by security agencies, militants planned to use "remote controlled airborne aerodynamic modules" to target VIPs who will campaign in these states.

States have been asked to guard high-rise buildings around airports, helipads and venues of political rallies, and clear cut instructions have been issued to shoot down anything that violated airspace restrictions.