Ten Vietnamese students and a few lecturers remain in safe areas in Hong Kong, the Ministry of Foreign Affairs said in a release on Monday.

The foreign ministry has instructed the consulate to keep a close eye on the situation and in contact with local authorities and Vietnamese citizens to protect the latter in case of necessity.

Several universities in Hong Kong have announced a premature closure to the first semester or switched to teaching online.

Protesters shot arrows and lobbed petrol bombs at police as fresh violence erupted at many universities in the territory, Reuters reported.

Amid the escalating violence, the Vietnamese students had been seeking help from the consulate to return home, the foreign ministry said.

Around 180,000 foreign students are in universities in Hong Kong, including 50 Vietnamese.

The protests began in March but snowballed in June as many people opposed an extradition bill which would have allowed defendants charged with serious crimes to be sent for trial abroad, including to courts in mainland China.

Hong Kong leader Carrie Lam formally withdrew the bill, but protesters are also calling for her to stand down.