China's Ambassador to Pakistan Luo Zhaohui yesterday condemned Sunday's attack on four Chinese, three of who were killed, and requested Islamabad "to investigate the incident, arrest the culprits, handle the follow-up issues properly and take effective measures to protect all Chinese in Pakistan".

Pakistan, too, condemned the attack. Foreign Office spokeswoman Tasnim Aslam said on Sunday night that her government regretted the killing of Chinese citizens. She, however, stressed the incident won't affect China-Pakistan friendship.

Related readings: Three Chinese killed in Pakistan  Gov't to protect workers abroad

The four Chinese victims, who are relatives, have been identified as independent businessmen from Laiyang in Shandong Province, the Chinese embassy said. Earlier reports had said they used to work for a motorcycle company.

The injured Chinese was shot in the arm during the attack, and is out of danger, the embassy said.

The embassy has already notified the victims' families, and is arranging for their travel to Pakistan to accompany the bodies and the injured back home.

The four were attacked by a group as they were leaving their work site in the town of Khazana, near Peshawar, capital of Pakistan's North West Frontier Province.

The Chinese embassy's deputy chief Mao Siwei is leading a team of Chinese diplomats to Peshawar to "deal with the issue", said an embassy press release issued in Islamabad yesterday.

A police officer was quoted as saying the attack seemed like an armed robbery.

But a senior security official in Islamabad was reported to have said it appeared to be linked with the Pakistan administration's efforts to draw out Islamic militants holed up in the Red Mosque in the capital.

"It's not confirmed yet that the incident was related with Red Mosque. But I think such attacks against Chinese are linked with Pakistan's extremist organizations," said Fu Xiaoqiang, a researcher with China's Institute of Contemporary International Relations.

"Extremist organizations could have tried to pressure the Pakistani government by attacking Chinese," Fu told China Daily.

The Pakistani government authorities issued the "last warning" to the extremists holed up in the Red Mosque on Sunday night. Pakistani President Pervez Musharraf convened a high-level meeting yesterday on how to crack a nearly weeklong resistance.

In 2004, three Chinese technicians working for a project in the volatile southwestern province of Baluchistan were killed in a bomb attack.

The same year, Islamists kidnapped two Chinese engineers working on a dam in the South Waziristan region on the Afghan border. One of them was freed by security forces, but the other was killed during the operation.