Islamabad, Pakistan (CNN) -- The Pakistani government is under pressure to block NATO supply routes to Afghanistan this month if the United States continues its campaign of drone strikes in northwestern Pakistan.
The demands from Pakistan Tehreek-e-Insaf (PTI), the opposition party led by cricketer-turned-politician Imran Khan, come amid anger in Pakistan over the killing of Hakimullah Mehsud, the leader of the Pakistani Taliban, in a U.S. drone strike last week.
The Pakistani government had been working on proposed peace talks with the extremist group when Mehsud was killed.
"Just as we were about to start talks -- the very day the Interior Minister planned to approach the Taliban -- a drone strike targeted the Taliban," Khan said Monday in the National Assembly. "So I ask you, Is the U.S. a friend or foe?"
His party is demanding that the national government block the ground supply lines to Afghanistan starting November 20 unless the United States ends the strikes, which have focused on Pakistan's loosely governed tribal areas where many militants are based.
Strike 'harmed' peace efforts
PTI, which campaigned heavily against drone attacks in Pakistan, holds the balance of power in the northwestern province Khyber-Pakhtunkhwa, through which one of the main NATO supply routes runs.
Alongside Khan's demands, the Khyber-Pakhtunkhwa provincial assembly has passed a motion to block NATO supply lines if the drone strikes don't stop by November 20.
There are two supply lines from Pakistan into Afghanistan: the one that passes through Khyber-Pakhtunkhwa and another that runs through the volatile southwestern province of Balochistan, where NATO tankers are often attacked.
Pakistani Prime Minister Nawaz Sharif's office said in a statement Monday that the drone strike last week "has harmed the dialogue and peace efforts of the government."
"But we believe that we will not ... allow the dialogue and peace efforts to get derailed," it said.
"Diplomatic efforts will be continued to stop these attacks," the statement said. "Given Pakistani peoples' resolve and sacrifices in this war against terrorism, it is incumbent upon the international community to support this endeavor of the government for the accomplishment of peace. The government of Pakistan will not allow any internal or external force to sabotage the dialogue process."
The U.S. State Department said Monday that it had seen the PTI statements about the supply lines.
"We have a strong, ongoing dialogue with Pakistan regarding all aspects of our bilateral relationship," said Marie Harf, a State Department spokeswoman.
The supply routes, which are "important to the U.S., NATO, and Pakistan," are fully open at the moment, Harf said.
Pakistan closed the routes for several months after a NATO airstrike killed 24 Pakistani soldiers at a checkpoint near the Afghan border in November 2011.
The Pakistani Taliban, who have long been conducting an insurgency against the Pakistani government, claimed responsibility for the December 2009 suicide bombing at the U.S. Forward Operating Base Chapman in Khost, Afghanistan. Five CIA officers were among the seven U.S. citizens killed, along with a member of Jordanian intelligence.
The group also claimed responsibility for a failed May 2010 attempt to detonate a car bomb in New York's Times Square. The following September, the U.S. State Department designated the Pakistani Taliban as a foreign terrorist organization.
Mehsud, who had a $5 million U.S. bounty on his head, was killed in northwestern Pakistan Friday, senior U.S. and Pakistani officials told CNN.