PARIS, March 25 (Xinhuanet) -- A group calling itself AZF has threatened to launch attacks in May unless money is paid by the French government.

    The group has sent letters to the French Interior Ministry and President Jacques Chirac's office, but did not specify the sum of money wanted and possible targets, Paris prosecutor's office said Friday.

    The letters were received on Thursday, the prosecutor's office said in a statement.

    Investigators are trying to check out whether the blackmail letters were from the same group that threatened to bomb France's railway network two years ago.

    Similar letters were sent from the AZF group to French authorities in December 2003, demanding 4 million euros (about 5.2million US dollars) and 1 million US dollars and threatening to blast railway lines.

    In February 2004, the group showed its muscle by directing French police to remove bomb materials from the railway line linking Paris and the southern city of Toulouse.

    The group wrote to the French government promising to quit terror operations in March 2004. But in July, eight food and cosmetics companies in France received letters from the group, each demanding 1 million euros (about 1.3 million dollars).

    AZF was the name of a Toulouse factory ruined in an explosion in 2001.

    So far, no apparent connections have been found between the group and the factory, while investigators once believed the terrorist group was a sham and had only two members. Enditem