New Delhi, Aug 5 (IANS): The Central Bureau of Investigation (CBI)has sent additional evidence to the ministry of external affairs against Warren Anderson, the global chief of Union Carbide during the Bhopal gas tragedy, to support the case for his extradition, the Rajya Sabha was informed Thursday.

Answering on behalf of Prime Minister Manmohan Singh, Minister of State in the Prime Minister's Office Prithviraj Chavan told Prabhat Jha (Bharatiya Janata Party) during question hour that the "CBI have been consistently pursuing the matter of extradition of Anderson since 1993".

However, the US State Department did not agree to the extradition, stating that the "request of the government of India does not meet the requirements of the dual criminality of the extradition treaty" between the US and India, he added.

The minister also stated that the the CBI has filed an appeal on July 27 this year before the sessions court, Bhopal, for enchancing the two-year jail term awarded to seven people convicted in the Bhopal gas leak case. The CBI has also pleaded for enhancement of the Rs.500,000 fine on Union Carbide, Chavan said.

At least 3,500 people were killed instantly and thousands more later after the deadly MIC gas leaked from the Union Carbide plant in Bhopal on the night of Dec 2-3, 1984.