Colombia`s top labor unions Wednesday rejected President Alvaro Uribe`s offer to talk on labor rights and anti-union violence, amid Uribe`s attempts to win US Congress approval of a US-Colombian free trade agreement.

In a letter to Uribe, the unions reminded him that 474 trade unionists have been murdered since he took office six years ago, that nearly all the murder cases have gone unsolved, and that his policies have directly harmed trade unions.

A copy of the letter sent to AFP and signed by, among others, the Central Workers` Union (CUT), the country`s biggest, said Colombian `workers have fared quite badly,` under the Uribe administration.

It comes amid telephone calls Uribe made this week to the incoming US administration of president-elect Barack Obama on the pending US-Colombian Free Trade Agreement, which Uribe and outgoing US President George W. Bush negotiated and signed in December 2006.

Uribe spoke with Obama on Wednesday and with vice-president-elect Joe Biden on Monday.

Democrats in the US Congress are resisting pressures from Bush to approve the trade agreement before he leaves office on January 20, demanding that Uribe first take care of union problems in his country and clear up allegations linking his administration to violent right wing paramilitaries, largely blamed for the anti-union violence.

The CUT and other leading trade unions, in their letter, said they will not meet with Uribe until his labor union policies change for the better, and as long as `you refuse to discuss and define your position ... regarding the social problems workers are facing.`