Chinese should cooperate with Pakistani police and military and contact the Chinese embassy if necessary, it added.

The embassy would not give further details when contacted by the South China Morning Post.

In June, Islamic State said it had killed two Chinese citizens it kidnapped.

The Pakistani interior ministry said the two Chinese had claimed to be learning the Urdu language from a Korean national in Jinnah town in Quetta but “were actually engaged in preaching”.

Quetta is the capital of Balochistan province, which is at the centre of the China-Pakistan Economic Corridor (CPEC) – the biggest single project under Beijing’s belt and road trade and infrastructure plan. The project includes plans for roads, railways and gas pipelines linking China’s far west hinterland of Xinjiang to the China-operated port of Gwadar on Pakistan’s southern coast.

Pakistani newspaper Dawn reported in October that the Chinese embassy had alleged that a member of Uygur separatist group the East Turkestan Islamic Movement had “sneaked into Pakistan” and posed a threat to Sun Weidong, who was the Chinese ambassador at the time.

The embassy had shared that information in a letter to Pakistan’s interior ministry that was leaked to the media. It included a request for more security for Chinese in Pakistan, and for the alleged terrorist to be arrested and handed over to China.

China has long worried that Uygur militants receive training in Pakistan, Afghanistan and Syria, then return to the restive Xinjiang region to plot attacks. There are also fears that Chinese projects along the CPEC could be a target for extremists, even though the Pakistani government promised to deploy 15,000 troops for security.

A Chinese man who has been living in Islamabad for three years said the embassy rarely issued security warnings.

“So I feel like this is something serious,” the man, who would only give his surname Liu, said.

Liu, who works for a Chinese financial company, said he had received messages and warnings in the past from other Chinese firms.

“We’re often being warned [in those messages] that Chinese will be targeted because of our growing presence in the country, and that we face security risks not only from the conflicting Muslim groups in the country, but also from India and the West,” Liu said.

He was not worried about his personal safety, but said his company had stepped up security measures after the embassy issued the warning. Chinese staff at his company were told they would be given new guidelines on how and when to travel to the office.

Li Wei, an anti-terrorism expert at the China Institutes of Contemporary International Relations, said it was impossible to know what kind of information the Chinese embassy received to prompt such a warning. But he noted that it came after US President Donald Trump recognised Jerusalem as Israel’s capital on Wednesday.

“It is expected that this will trigger a wave of strong reactions from Pakistan, although any attacks wouldn’t target Chinese, but many foreign companies and embassies are located in the same areas, so the Chinese embassy will be on alert at the moment,” Li said.

After the two Chinese were killed earlier this year, Beijing accelerated its security plans to protect the more than 30,000 Chinese nationals living in Pakistan, he said, adding that there had been occasional attacks by separatist groups in Balochistan and Sindh, where China has invested billions to build the Gwadar port and roads.

“The entire country is still high risk for Chinese people,” he said.

A researcher at a government think tank in Beijing who declined to give his name said Chinese embassies were increasingly becoming targets for terrorists. “If the August 2016 attack on the Chinese embassy in Kyrgyzstan was any indication, diplomatic and company premises are easy targets for terrorists – especially in places where they find it difficult to operate,” he said.