Washington, Sep 1 (IANS): Noting that three in four terror suspects are acquitted in Pakistan, the United States has doubts its key ally would make any headway in prosecuting key plotters of 2008 Mumbai terror attacks.

"The accused in numerous high-profile terrorism incidents involving US victims had all been acquitted by the Pakistani legal system," US State Department noted in its 2010 Country Reports on Terrorism, published last week.

"The Federal Bureau of Investigation has assisted with the respective prosecutions," the report said. FBI had assisted India in the investigation of the Mumbai terrorist attack as six Americans were among the 166 victims.

The report found that while Pakistan maintained it was committed to prosecuting those accused of terrorism, a study of its Anti-Terrorism Court's rulings last year disclosed "that Pakistan remained plagued by an acquittal rate of approximately 75 per cent", and a legal system "almost incapable of prosecuting suspected terrorists".

It complained that a new anti-terror bill, which would allow its security agencies to hold suspects for 90 days before bringing them to court and give them a freer hand to use electronic surveillance had not progressed in the country's National Assembly.

Although Islamabad had increased pressure on money-launders and unofficial 'hawala' money transfer agents, "deficiencies remained," the report found.

"Notably, the criminalisation of the financing of terrorist acts committed against foreign governments and international organisations was ambiguous, as was the criminalisation of financing groups that have not been explicitly banned by the government or designated by the UN," it stated.

Pakistan's "weak implementation" of a UN Security Council resolution which lists banned terrorist organisations remained a concern.

The report also criticises Islamabad's failure to outlaw militant Islamic terror groups which escape bans by changing their names.