China has pressed long-time ally Pakistan to ensure the security of Chinese nationals in Pakistan and swiftly bring to justice those behind a bombing Tuesday that killed three Chinese teachers. “The blood of the Chinese people should not be shed in vain, and those behind this incident will surely pay the price,” the Chinese Foreign Ministry said Wednesday, without elaborating. The deadly attack took place at the entrance to the China-run Confucius Institute in the southern Pakistani city of Karachi, when a suicide bomber blew herself up near a van transporting Chinese staff. The director of the institute was among the three Chinese teachers killed. A Pakistani driver was also killed and a Chinese teacher was injured. The Chinese Foreign Ministry said in its statement that assistant Foreign Minister Wu Jianghao called Islamabad’s ambassador to Beijing, Moin ul Haque, to express his “extremely grave concern.” “He demanded that the Pakistani side should immediately make [a] thorough investigation of the incident, apprehend and punish the perpetrators to the full extent of the law,” the statement said. The outlawed Baluch Liberation Army (BLA) insurgent group took responsibility for plotting the attack and released a picture of the purported bomber. Pakistan and the United States list the group as a terrorist organization. The Chinese Foreign Ministry said that its diplomatic missions in Pakistan would continue to urge relevant authorities to “handle properly the follow-up matters of those killed, treat the injured, and resolutely crack down on the terrorist organization involved.” Pakistani Prime Minister Shehbaz Sharif condemned the attack and promised to do whatever it takes to bring the perpetrators to justice. Sharif visited the Chinese Embassy in Islamabad following the attack to express his condolences. “We are deeply shocked and distressed at this dastardly attack on our Iron Brothers,” read the note written by Sharif at the embassy, in which he reiterated that “we remain committed to eliminating all militarists and terrorists from Pakistani soil,” according to Chinese state media. Critics questioned the official claims, citing a lack of progress in Pakistan's investigations into previous attacks on Chinese workers in the country, which, analysts say, has become the most dangerous place for Chinese overseas. Mustafa Hyder Sayed, who heads the Islamabad-based Pakistan-China Institute, said the security of Chinese nationals in Pakistan has become the biggest concern for Beijing in terms of furthering its bilateral economic cooperation. "I think this is an inflexion point in Pakistan-China cooperation because this has now crossed a red line as far as China is concerned,” Sayed told VOA. “Pakistan has repeatedly vowed to have foolproof security arrangements for the Chinese; however, we have not been able to walk the talk, and our rhetoric has not been able to materialize into action,” he said. Sayed said he expected that the future presence of Chinese individuals in Pakistan, whether through its Chinese companies, Confucius Institutes or other projects, “would be now conditional and linked to robust and effective preemptive measures for security of the Chinese in Pakistan.” Confucius Institutes, established in universities around the world, offer Chinese language graduate classes. Critics say Beijing is trying to use them to promote its foreign policy agenda. The BLA, which operates out of natural resources-rich southwestern Baluchistan province along with several other banned separatist groups, has been waging insurgent attacks against Pakistani forces and Chinese nationals in the province. Baluch separatists oppose Chinese investments, particularly in Baluchistan, claiming China and Pakistan are depriving people in the impoverished region of their natural resources. The BLA has expanded its violent activities to other parts of Pakistan, particularly Karachi, in recent years, and used a female suicide bomber for the first time in Tuesday’s attack. Beijing has invested more than $25 billion over the past seven years in large-scale infrastructure development projects in Pakistan, including Baluchistan, under China’s global Belt and Road Initiative. The bilateral program, known as the China-Pakistan Economic Corridor, or CPEC, has built road networks and power plants across Pakistan and the Gwadar deep-water port in the turbulent province. In a post-attack video message on Tuesday, a masked BLA commander claimed that his group has formed a "special unit" to target Chinese officials and installations to ensure CPEC projects "will fail miserably" in Baluchistan. "President Xi Jinping, you still have time to quit Baluchistan, or you will witness a retaliation from Baluch sons and daughters that you will never forget," warned the militant commander, referencing the Chinese leader. The BLA had taken responsibility for staging a 2018 gun and bomb attack against the Chinese consulate in Karachi in which two Pakistani security guards were killed. In 2020, BLA militants in the city tried to storm the Pakistan Stock Exchange, where a Chinese consortium has a 40% stake, but security forces engaged the assailants in the parking area and killed all of them. Pakistan accuses rival India of supporting and funding Baluch militants to undermine CPEC, accusations that New Delhi rejects. In July, a suicide car bombing of a bus convoy transporting Chinese workers to the China-funded Dasu hydropower project under construction in the northern region of Kohistan killed nine of the workers and three Pakistani security guards. It was the largest loss of life of Chinese nationals in Pakistan. Jaime Moreno contributed to this report.