NEW DELHI - THE Indian government said on Tuesday it was 'unhappy' over a Pakistani court decision to release the head of an Islamic charity India says was linked to last year's Mumbai siege.

'We are unhappy that Pakistan has not shown the degree of seriousness and commitment it should have to bring to justice the perpetrators of the Mumbai attacks,' Indian Home Minister P. Chidambaram told reporters.

A Pakistani court on Tuesday declared the detention of Jamaat-ud-Dawa chief Hafiz Mohammad Saeed and three other members of his party unlawful.

An Indian foreign ministry official told AFP that New Delhi was carefully watching to see 'whether the government in Pakistan will appeal against the court order'. India says the charity is a front for Lashkar-e-Taiba (LeT), blamed for a 2001 raid on the Indian parliament and last November's Mumbai attacks, in which 166 people were killed.

Pakistan had sealed offices of the Dawa within weeks of the Mumbai attacks after a UN Security Council resolution described the charity as a terror group.

Islamabad had frozen the group's assets besides placing Saeed - also the founder of LeT - under house arrest.

Pakistan has however refused to hand over Saeed or 'any fugitives from Indian law' named in a list of 42 wanted men India says are being sheltered by Pakistan.

Indian prosecutors say they have evidence that 'undoubtedly and conclusively' links the Mumbai attacks to Pakistan, including mobile and satellite phone communication between the gunmen and their LeT 'handlers'.

India has put on trial a Pakistani national, alleged to be the only gunman to survive the three-day killing spree, who has pleaded not guilty to all charges, including 'waging war against India', which carries the death penalty.

Mohammed Ajmal Kasab, 21, who was also charged with destabilising the government, murder, kidnap and robbery, was allegedly part of a 10-member Islamist commando group that stormed India's financial and entertainment capital. -- AFP