Prime Minister Manmohan Singh today showered praise on Home Minister P Chidambaram, who is in the line of opposition fire, saying he derived "immense" support from his "enlightened leadership".

"Since 2004, I have been deriving immense support from his enlightened leadership as Finance Minister and then as Home Minister. Whatever task is given to him, he performs with super aplomb," Singh said at a function here in Chidambaram's Sivaganga Lok Sabha constituency.

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Singh's remarks came against the backdrop of Chidambaram coming under opposition attack over his alleged role in 2G spectrum allocation scam and the charge of misuse of office in helping a Delhi-based hotelier.

"He and I have been colleagues since 1990s and worked hand in hand. I worked as Finance Minister when he worked as Commerce Minister then," the Prime Minister said, referring to Chidambaram who was seated among the audience at a function in the Alagappa University.

Gunning for his resignation, BJP has been boycotting Chidambaram in Parliament heckling him whenever he rises to speak, with the party using his alleged misuse of office in helping a Delhi-based hotelier as a fresh ammunition against him.

The UPA Government and the Congress have rallied behind Chidambaram, rejecting the opposition charges and calls for his resignation.

With his engagements in Karaikudi, Singh wrapped up his two-day visit to Tamil Nadu over which the Mullaperiyar dam row between the state and Kerala cast its shadow.

A day after Tamil Nadu Chief Minister Jayalalithaa took up the issue with Singh asking him to advise Kerala not to build a new dam, it was the turn of UPA's key ally and her arch-rival DMK today to raise the pitch for central intervention.

Leading a party delegation that included his daughter Kanimozhi, MP, out on bail in the 2G scam case, DMK Chief M Karunanidhi urged Singh to take steps to end attacks on Tamils in Kerala and for implementation of Supreme Court's 2006 order allowing Tamil Nadu to raise water level in the reservoir.

After the 20-minute meeting at Raj Bhavan, Karunanidhi said the Prime Minister assured him that the Centre would take all steps to maintain friendly ties between the two states and ensure return of normalcy.

The DMK patriarch also quoted Singh as having told the delegation that "the possibility of central government itself protecting the dam could be examined".

"After listening to the delegation, the Prime Minister said the Centre would take all steps to ensure the long standing relationship between the two states is not strained and peace and normal life returns," Karunanidhi said in a statement.

The dam row has intensified since last month with both Tamil Nadu and Kerala sparring over the latter's insistence on building a new dam in place of the 116-year old Mullaperiyar reservoir, causing tension in border areas of both states.

Kerala has been citing safety concerns for its demand to decommission the dam, which feeds five southern districts in Tamil Nadu, under whose control it comes on a 999 year lease.

Singh's visit, first to the state after the Congress-DMK alliance was routed by AIADMK in the Assembly polls, also saw attempts by activists of DMDK headed by actor Vijaykant and Vaiko's MDMK to stage black flag demonstrations in Chennai and Karaikudi protesting Centre's "silence" on the dam issue.

In Chennai at a function to mark the 125th birth anniversary of mathematical genius Srinivasan Ramanujan, Singh declared 2012 as the 'National Mathematical Year' as a tribute to him. He also declared December 22, the birthday of Ramanujan, as 'National Mathematics Day.'

Voicing concern over the "badly inadequate" number of competent mathematicians in the country, the Prime Minister said the perception that pursuit of mathematics does not lead to attractive career possibilities "must change."

"It is a matter of concern that for a country of our size, the number of competent mathematicians that we have is badly inadequate," he lamented.

Singh also inaugurated two hospitals in Karaikudi, urging private sector to supplement government's efforts to provide affordable health care facilities to the people.