Tel Aviv, Feb 27 (IANS): Zionist Union leader Isaac Herzog Thursday called on Israeli Prime Minister Benjamin Netanyahu to cancel his planned speech to the US Congress March 3, saying it will cause "strategic damage" to Israel's ties with the US, Xinhua news agency reported.

Herzog, who is chairman of the Labor Party, started his attack against Netanyahu at a press conference held in Tel Aviv along with Hatnua leader Tzipi Livni. The two merged their parties into a united list, the Zionist Union, which is the top rival for Netanyahu's ruling Likud party in the March 17 elections.

Herzog blamed Netanyahu for irreparably damaging Israel's close ties with the US, with his decision to speak in front of the Congress with a hardline stance on nuclear Iran, contrary to the official stand of the US government.

"I call on Netanyahu again: Stop. Don't Go. You will cause strategic damage to Israel's standing and to the relationship with the US," Herzog said.

Netanyahu's speech in front of the congress is set for March 3, two weeks ahead of the Israeli elections, and was coordinated by Republican House Speaker John Boehner.

Herzog attacked Netanyahu for not agreeing to meet with US Senate Democrats in his trip to Washington, saying the prime minister is "playing politics inside American politics."