The engineers, who were among 14 working at a concrete factory, were shot with their driver on Wednesday on a road in the town of Hub, about 700km southeast of Quetta, the capital of the restive province Baluchistan, Pervez Zahoor, the region's police chief, said.
Shortly after the attack, a Baluch nationalist group, the Baluchistan Liberation Army, claimed responsibility for the shooting. The group said it's fighting for the rights of Baluchistan residents, who claim the government is exploiting their land.
"We killed these Chinese and their Pakistani driver," Mirak Baluch, a purported spokesman for the group, said in a telephone call to The Associated Press.
Babar Bashir, a senior official at the concrete factory, condemned the attack and said the other 11 Chinese engineers were planning to go back to their country, although he would not say when they would leave.
It was not immediately known how many Chinese were working on other projects in Pakistan.
Wracked by unrest
Sparsely populated Baluchistan has been wracked by shootings, small-scale bombings and rocket attacks in recent years. Most have been blamed on tribesmen demanding increased royalties for gas extracted from the province.
The tribesman also oppose the Pakistan military's campaign to build new garrisons, which the government says are needed to bolster security.
Baluch tribes oppose the building
of new Pakistan army garrisons
The attack came days before Pervez Musharraf's planned to begin a visit to China on 19 February.
China is one of Pakistan's most important allies because it provides the country weapons and other support.
The recent violence has raised fears of a repeat of fighting that rocked Baluchistan in the 1970s, when thousands died in a large-scale uprising.
Three Chinese engineers were killed in a bombing in May 2004 in another area of Baluchistan.
Pakistan's Foreign Ministry in a statement condemned Wednesday's attack and promised to enhance security for the Chinese working in Pakistan "to prevent such dastardly acts in future".