PARIS, March 3 (Xinhuanet) -- A previously unknown group calling itself AZF has threatened to blow up France's SNCF state railway if it can't be satisfied with a ransom of five million US dollars (four million euros), officials said Wednesday.

    The group had sent letters to President Jacques Chirac and Interior Minister Nicolas Sarkozy, warning that several bombs had been planted in different railways and timed to explode on different dates, police sources said.

    "These supposed terrorists are asking us to hand over a sum of money, around four million euros," Michel Gaudin, director generalof the national police, told LCI television. "We have discovered abomb that could be dangerous," he added.

    On Feb. 21, the police found one sophisticated time bomb under rails near Limoges between Paris and Toulouse following hints by the AZF.

    While French media are focused on the possible incentive of theblackmail, Gaudin indicated, "I do not think this is a group linked to Islamic radicalism." He also rejected the allegation thegroup is connected with Chechen terrorist movement.

    Europe 1 radio said the group called itself "secular terrorists", but the police believed they were criminals trying to blackmailSNCF.

    Gaudin said the police had only "a very, very brief telephone contact" with the group.

    An explosion at the AZF chemical factory in Toulouse in September 2001 killed 30 people and injured more than 2,000. An investigation into the causes of the blast is still going on. Enditem