WASHINGTON: Pakistani forces are allowing insurgents to launch rocket and mortar attacks on US troops across the border in Afghanistan and may be collaborating with the militants, a US general said Thursday.

“In some locations from time to time you will see what just appears to us to be a collaboration... or at a minimum a looking the other way when insurgents conducted rocket or mortar fire in what we believe to be (within) visual sight of one of their (Pakistan military) posts,” said Lieutenant General Curtis Scaparrotti, deputy commander of the Nato-led force in Afghanistan.

Soldiers from Pakistan's Frontier Corps, who are locally recruited and not as highly trained as regular army units, man the border posts, he told reporters via video link.

The general also said cross-border attacks have increased dramatically in eastern Paktika province in recent months, with rocket and other fire four times higher than in previous years.

The rocket fire has coincided with a virtual breakdown in communications between US and Pakistani officers along the border since May, when American special operations forces killed Al-Qaeda chief Osama bin Laden at his compound in Pakistan in a unilateral raid that angered Islamabad, he said.