Thousands of Pakistanis protested outside the U.S. consulate in Karachi Sunday following the NATO airstrike that killed 24 Pakistani troops when helicopters and fighter jets fired on two army checkpoints.

Reuters reported:

[T]he angry crowd shouted "Down with America." One young man climbed on the wall surrounding the heavily fortified compound and attached a Pakistani flag to barbed wire.

[...]

"America is attacking our borders. The government should immediately break ties with it," said Naseema Baluch, a housewife attending the Karachi demonstration.

"America wants to occupy our country but we will not let it do that."

Additionally, about 500 members of Pakistan's influential religious political party Jamaat-e-Islami staged a demonstration in the Mohmand tribal area, the northwest area where the attack took place.

"Jihad is the only answer to America," they yelled.

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Pakistan on Saturday shuttered U.S. supply routes that support troops in Afghanistan in response to the attack. The supply lines handle about half the alliance's land shipments.

Afghan officials said Sunday that Afghan troops who came under fire near the Pakistan border called in the airstrikes, according to the Associated Press. Pakistani officials had said Saturday the assault was unprovoked.

NATO Secretary-General Anders Fogh Rasmussen has vowed to support a full investigation.

U.S.-Pakistani relations have been strained since U.S. special forces carried out a secret operation to kill Osama bin Laden in May without prior Pakistani knowledge.

Foreign Minister Hina Rabbani Khar spoke to U.S. Secretary of State Hillary Clinton early Sunday to convey "the deep sense of rage felt across Pakistan," Reuters reported.

"This negates the progress made by the two countries on improving relations and forces Pakistan to revisit the terms of engagement," a Foreign Ministry statement quoted Khar as saying.

Khar also said Pakistan wants the U.S. to vacate a drone aircraft base in the country.