The Chinese government's top diplomat, Wang Yi, said he was "shocked" by an attack on Friday on his country's consulate in the Pakistani city of Karachi and urged Pakistan to prevent any more attacks.

Wang, who is a state councilor and China's foreign minister, strongly condemned the attack during a phone call with Pakistan Foreign Minister Shah Mahmood Qureshi, according to a statement published on the Chinese ministry's website.

Three suicide attackers stormed the consulate amid a series of gunshots and an explosion earlier but were killed before they could enter the building in a car packed with explosives. The attack was claimed by a separatist militant group from Pakistan's southwestern province of Balochistan, which is at the center of a major Chinese investment project in the country. "We have carried out this attack and our action is continuing," the spokesman for the Balochistan Liberation Army (BLA), Geand Baloch, told AFP by telephone from an undisclosed location.

China, one of Pakistan's closest allies, has poured billions into the South Asian country in recent years as part of a massive infrastructure project that seeks to connect its western province Xinjiang with the Arabian Sea port of Gwadar, in Balochistan. The project, the China-Pakistan Economic Corridor (CPEC), is one of the largest in Beijing's "One Belt One Road" initiative, comprising a network of roads and sea routes involving 65 countries.

For Pakistan, participating in the project presents an enormous challenge in a country plagued by weak institutions, endemic corruption and a range of insurgencies in areas slated to host the corridor. The subject of economic dividends from CPEC is extremely sensitive in some of the areas the corridor will run through, particularly in Balochistan.

Since the beginning of the project militants have repeatedly attacked construction sites, blowing up numerous gas pipelines and trains, and targeted Chinese workers. In August this year three Chinese nationals were among six wounded in a suicide attack on a bus transporting Chinese engineers working on a mining project in Balochistan, in an attack that was also claimed by the BLA. China has said it is confident the Pakistani military, which has been repeatedly accused by international rights groups of abuses in Balochistan, is in control of the issue. Islamabad regularly accuses its eastern neighbor India of funding and arming Baloch separatists, and of targeting development projects in the province, particularly CPEC.