The Chinese embassy in Islamabad confirmed that Long had arrived at the mission and would soon travel back to China.

It was unclear whether a ransom had been paid or if Taliban fighters had been freed in exchange for Long's release.

Increased attacks

The engineer was seized along with another Chinese colleague, their Pakistani driver and a guard near the Afghan border last August.

Pakistan's security forces recovered Long's colleagues seven weeks later after they escaped from the fighters while they were being shifted to a mountain hideout.

Attacks on foreign aid workers, company employees and diplomats have increased in Pakistan over the past year, especially in areas near the border with Afghanistan, where pro-Taliban fighters are battling government forces.

Earlier this month, a Polish geologist held by Taliban fighters was beheaded.

Two weeks ago, a US citizen heading the UN High Commission for Refugees (UNHCR) office in the southwestern province of Baluchistan was abducted and his driver shot dead.

A previously unknown group, calling itself the Baluchistan Liberation United Front, claimed it had seized the UN official and warned it would kill him if their demands were not met.