US embassy in UK has advised citizens to avoids schools, churches, tourist locations and vary their travel routes.

The United States embassy in London has issued a security alert telling its citizens in the United Kingdom to be cautious after the British government raised the national threat level to “severe”.

The embassy advised citizens on Friday to remain “alert in public places” and to stay away from schools, churches, tourist locations and transportation hubs.

It also said that US nationals should vary their “travel routes and times” to reduce predictability and to keep a low profile.

The UK’s domestic intelligence agency, MI5, said on Friday that the Joint Terrorism Analysis Centre had raised the threat level from “substantial” to “severe”.

This is the second-highest level, signalling that an attack within the next six months is “highly likely”, MI5 said in a statement.

“The UK has been experiencing a gradual increase in terrorist threats for some time,” the agency said, adding the changed threat level also followed after the stabbing of two Jewish men in the Golders Green area of London on Wednesday, “although it is not solely a result of that attack”.

The increased danger has been “driven by a rise in both Islamist and Extreme Right-Wing terrorist threat from individuals and small groups in the UK,” MI5 said, noting threats in particular to “Jewish and Israeli individuals and institutions, in the context of the conflict in the Middle East”.

This is the second security notice from the US embassy in the UK in the last few weeks.

Recently, it posted a statement noting the recent attacks and threats “targeting Jewish and American institutions”, and advising citizens to be cautious.

Last week, the Finchley Reform Synagogue in north London was targeted. Other incidents have occurred, including an attack on the Kenton United Synagogue in Harrow.