Police are reviewing how to strengthen protection of their officers and Jewish communities in the wake of the Paris attacks.
Metropolitan Police Assistant Commissioner Mark Rowley - Britain's most senior anti-terror officer - revealed chief constables around the country are looking again at how to prevent attacks against those seen as targets for Islamic extremists.
He said there is currently "heightened concern" over the threat to Jewish communities and the "deliberate targeting" of police officers in recent terrorist attacks.
This comes as authorities thwarted an "unprecedented" number of terrorist attacks in the UK over recent months, he revealed.
He said the number of terror arrests also rose by a third last year.
"The global picture of terrorist activity does give us heightened concern about the risk to the Jewish community in the UK," he said.
"We are seeing continuing anti-Semitic rhetoric from extremists and attacks on this community in France and elsewhere.
"In addition to our existing security measures, we are in dialogue with Jewish Community leaders about further actions that we will be taking, including more patrols in key areas.
"We remain alert to the vulnerabilities of other communities. Where we do have particular concerns, we make these known to those involved.
"For example, we continue to be alive to those who want to exploit the current situation and create fear in our Muslim communities, with whom we work closely, to offer our protection and reassurance.
"We are also considering what further measures we might put in place to enhance the security of police officers, given some of the deliberate targeting of the police we have seen in a number of countries across Europe and the world.
"Chief constables across the country are reviewing how to strengthen the protection of their officers from such attacks.
"Our men and women on the frontline are used to confronting risk and danger and are well-trained in how to protect the public and themselves."
Sky News Crime Correspondent Martin Brunt said Mr Rowley was taking the opportunity to remind people "what the police are doing and what more they're having to do".
He said: "Clearly after the attack on a Jewish supermarket in Paris, he says that police are talking to that community or those communities to see how they can improve their security - he says one thing is to have more patrols in key areas."
