Pro-Israel groups have invested hundreds of thousands of dollars in an advertising campaign against Republic Senator Rand Paul this week over his attempts to block US security aid to Israel.

Paul says he opposes the open-ended US aid to Israel, citing the need for the existing legislation to be amended before the final version is approved by the Senate.

Paul is an outspoken critic of US foreign aid and has been one of President Donald Trump’s most significant Republican critics on foreign policy.

“While I’m not for foreign aid in general, if we are going to send aid to Israel it should be limited in time and scope so we aren’t doing it forever, and it should be paid for by cutting the aid to people who hate Israel and America,” a statement from Paul’s office said.

The Libertarian senator from Kentucky recently put a congressional hold on the U.S.-Israel Security Assistance Authorization Act which authorizes $38 billion in funding from the US to Israel.

A hold is a congressional procedure that allows senators to prevent a motion from reaching the floor for a vote.

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