"This resolution violates our sovereignty and we condemn it," Gilani told reporters in a televised interaction with media in the port city of Karachi.
Republican Representative Dana Rohrabacher said that Baluchis — divided now among Pakistan, Iran and Afghanistan — should be allowed to choose their status.
Baluchistan province in southwest Pakistan suffers from violence linked to the Taleban, sectarian extremists and Baluch rebels, who rose up in 2004 for political autonomy and a greater share of the region's oil, gas and mineral deposits.
A resolution Friday sponsored by Rohrabacher and two fellow Republicans said the Baluchi people "have the right to self-determination and to their own sovereign country, and they should be afforded the opportunity to choose their own status." There was no sign of significant support for the proposal by Rohrabacher, a longtime critic of Pakistan's government who sought unsuccessfully to cut off all aid after US forces found and killed Osama Bin Laden on Pakistani soil.
Pakistani Foreign Minister Hina Rabbani Khar described it as an "isolated move by a few individuals." "It was aimed to create distrust between the peoples of the two countries," she said in a statement.
Khar expressed the hope that "this latest tendentious move will not be allowed to sail through the House by a vast majority of US Congressmen who continued to support friendly relations between the two countries." Pakistan similarly accused the United States of meddling in its affairs after Rohrabacher, who heads an investigative subcommittee of the House Foreign Affairs Committee, recently called a hearing on Baluchistan.
Meanwhile, Afghanistan is optimistic that regional power Pakistan will help the Kabul government advance a reconciliation process with the Taleban, the Afghan president's spokesman said on Saturday.
Pakistan, seen as crucial to efforts to end the war in Afghanistan, has repeatedly said it wants peace in its neighbor.
Afghans, however, have always been suspicious of Pakistani intentions because of historical ties between Pakistani intelligence and insurgent groups like the Afghan Taleban.
Relations between Pakistan and Afghanistan were strained for months after the assassination in September of Afghan peace envoy and former president Burhanuddin Rabbani.
Afghan officials blamed Pakistan's intelligence agency, allegations angrily denied by Islamabad.
But talks this week between Afghan President Hamid Karzai and Pakistani leaders in Islamabad were encouraging, said Karzai's spokesman, Aimal Faizi.
"We noticed a big change among the Pakistanis. The atmosphere is much better," Faizi said in Islamabad. "We are more optimistic than before that they will support us." Faizi said Karzai made several demands when he met top Pakistani officials.
He would not list them but Afghanistan is known to want access to Taleban leaders belonging so the so-called Quetta Shura, named after the Pakistani city where it is said to be based.
They would be the decision makers in any substantive peace negotiations.
Pakistan has consistently denied giving sanctuary to insurgents and denies the existence of any Quetta Shura, or leadership council.
Pakistani Foreign Minister Hina Rabbani Khar said after a recent trip to Kabul that a lot of ill will between Kabul and Islamabad had eased.
And she indicated Pakistan would encourage militant groups seeking to topple the US-backed Kabul government to pursue peace if asked by Afghanistan.
The apparent change in mood comes at a critical time when the Afghan government is exploring ways to reach the next stage of reconciliation - negotiations with the Taleban. So far, there have only been contacts, Afghan officials say.
The Afghan Taleban announced last month it would open a political office in Qatar, suggesting it may be willing to engage in negotiations that could likely give it government positions or official control over much of its historical southern heartland.
Karzai's government supports any talks that take place in Qatar, but it wants to widen the reconciliation process to other countries because that could make the effort more comprehensive.
Faizi said Afghanistan had a preference for holding the next phase of the reconciliation process in Saudi Arabia and Turkey.
"We want these two countries to facilitate the real (formal) talks," he said.
