Updated

The leader of a Pakistani political party protesting U.S. drone strikes demanded Sunday that the attacks end in one month or he would launch more demonstrations aimed at cutting off a key supply route for Western troops in neighboring Afghanistan.

Imran Khan made the demand at the end of a two-day protest that clogged up a major road used by trucks to ferry supplies to U.S. and NATO troops across the border. Only a few thousand people came out, but the demonstration drew widespread attention at a time of increased U.S.-Pakistan tension and underscored the vulnerability of the supply line.

Authorities halted the NATO supply shipments Saturday as the protest began on the outskirts of Peshawar, around 35 miles (57 kilometers) from the Afghan border. By late Sunday, officials said the road was re-open to all traffic.

"We will block NATO supplies from Karachi to Khyber everywhere if drone attacks are not stopped in one month," said Khan, a one-time Pakistani cricket star-turned-politician, to the crowd of protesters.

If they don't stop, "We will march toward Islamabad," he said.

It is unclear how much impact future protests led by Khan will have. Although he has a high profile due to his sporting history, his political following is relatively small. But the issue of the drone-fired U.S. missile strikes is sensitive for Pakistanis in general, with many concerned about civilian deaths, and could boost his appeal.

Earlier Sunday, as some youth in the protest shouted and danced to drum beats, others held banners with slogans such as "Our blood is not for sale" and "Stop drone attacks, stop genocide of innocent Pakistanis."

The U.S. rarely discusses the covert, CIA-run program, but officials have insisted it is mostly militants who are killed by the drone-fired missiles. Pakistan has publicly denounced the strikes, but is believed to secretly aid in at least some of them.

But tensions between Pakistan and the United States have risen since late January, when an American CIA contractor shot dead two Pakistanis he said were trying to rob him. Since then, the military and civilian leaders have taken a tougher line on the missile strikes, at least in public.

Much of the non-lethal supplies for foreign troops in landlocked Afghanistan come through Pakistan. Militants often attack the convoys, and last September Pakistan closed the border for 20 days to protest a deadly NATO helicopter strike inside its borders.

The U.S. and NATO normally say such interruptions have little to no impact on the supply line. But they have been turning more to other roads into Afghanistan from the north in recent years.