U.S. Secretary of State Mike Pompeo said in a March speech that anti-Zionism - opposition to Israel’s existence as a homeland for the Jewish people - was a form of anti-Semitism, or hostility toward Jews, that was on the rise worldwide and that Washington would “fight it relentlessly”.

The State Department’s special envoy for monitoring and combating anti-Semitism, Elan Carr, said this U.S. position could spell reviews of ties with foreign governments or leaders.

“The United States is willing to review its relationship with any country, and certainly anti-Semitism on the part of a country with whom we have relations is a deep concern,” he told Reuters during a visit to Israel.

“I will be raising that issue in bilateral meetings that I am undertaking all over the world,” he said. “That is something we are going to have frank and candid conversations about - behind closed doors.”