ISLAMABAD, Feb 29: The government on Sunday promised an impartial inquiry into Saturday's killing of 11 people in the South Waziristan Agency after opposition parties in the Senate protested against the incident and staged a walkout.

States and Frontier Regions Minister Aftab Sherpao told the upper house that the NWFP governor had ordered a high-level inquiry into the incident. "We will be overseeing it and will see that it is done in an impartial way," the minister said during a discussion emanating from points of order raised by several opposition senators before and after the brief walkout that ended after the ruling coalition persuaded the protesters to come back to the house.

Senators from the Democratic Alliance and the Muttahida Majlis-i-Amal (MMA) were united in accusing the security forces of killing innocent civilians in an operation launched at the best of the United States.

Both Mr Sherpao and leader of the house Wasim Sajjad rejected the charges that security operations in Fata were being dictated by any foreign power and said Pakistan was fighting terrorism in the interest of its own security.

Democratic Alliance parliamentary leader Raza Rabbani described Saturday's clash as a reflection of a mind-set of the government, which he said was seeking to "convert Pakistan into a police state at the instance of American imperialism".

Prof Khurshid Ahmed of the MMA said the entire tribal area was seething with anger because of the military operations which he blamed on perceived American dictates. He called for a halt to the operations that he said could lead to "confrontation between the army and tribals".

Several other senators, including PML-N parliamentary leader Ishaq Dar and usually pro-government independents from Fata, disputed the government's version that the troops opened fire after being fired at from vehicles used by suspected terrorists.

Raza Mohammad Raza of the Pashtunkhawa Milli Awami Party struck a note somewhat different from the general opposition line as he called for an expeditious clearance of the tribal areas from "international terrorists" who, he said, could provoke a "hot-pursuit" into the tribal areas by US-led forces in Afghanistan. But he called for a cautious approach to protect local population.

WATER CONTAMINATION: Minister of State for Environment Tahir Iqbal promised to collect details about reported arsenic contamination of groundwater used for drinking in several districts of Punjab and Sindh after the matter was raised by former information minister Nisar Ahmad Memon.