Chennai, Dec 26 (IANS): Hundreds of DMDK members were detained here Monday when they staged a black flag protest against Prime Minister Manmohan Singh on three major issues confronting Tamil Nadu.

DMDK leader A. Vijayakant and a large number of his supporters were taken into preventive custody in Saidapet area as they raised slogans against the prime minister, who is on a two-day visit of the state.

Police put the number of activists detained and then let off at about 750. DMDK, however, said thousands were involved in the protests in Chennai, Madurai, Coimbatore, Tirupur, Tiruchirapalli and Karaikudi.

In Chennai, the protesters waved black flags and placards.

Vijayakant, who was allied with the AIADMK during this year's election but is now the opposition leader, led the protest in Chennai.

As news of his detention spread, similar noisy demonstrations erupted in the other towns.

The DMDK condemned the central government's "inaction" on the Mullaperiyar dam row with Kerala, the refusal to halt work at the Kudankulam Nuclear Power Project and on the Cauvery water dispute with Karnataka.

Speaking to reporters, Vijayakant charged Manmohan Singh with not focussing on the dam issue and accused Chief Minister J. Jayalalithaa too of not taking steps to solve the problem.