History will not forgive whoever allows Iran to become a nuclear power, Prime Minister Benjamin Netanyahu said on Sunday, as contenders in Israel’s parliamentary elections sharpened their messages two days before polling stations open.

Parties were scrambling in a last-minute attempt to convince undecided voters around a quarter of the electorate, according to opinion polls. Mr. Netanyahu and his ruling Likud party have highlighted the issue of security throughout the campaign.

On Sunday, the nationalist premier said he had told five US senators he had just met that the most pressing problem in the region was security, not Israeli construction on West Bank land in and around Jerusalem.

“The problem in the Middle East is the attempt by Iran to build a nuclear weapon, the chemical weapons in Syria and the radical Islam that is spreading in Africa and threatening to sweep the whole region,” Mr. Netanyahu told his cabinet.

“I told them that history won’t forgive whoever allows Iran to arm itself with a nuclear weapon. This was and remains the main mission facing not only me and Israel, but also the US.” Shelly Yechimovich, of the centre-left Labour Party, responded by saying that, “Mr. Netanyahu is planning a social hell, economic chaos, and diplomatic isolation for us.”

According to the last surveys published ahead of Tuesday’s election, Likud enjoys a strong lead and is forecast to become the largest party in the 120-seat Knesset.

But Likud has been losing voters to the ultra-nationalist Jewish Home of high-tech entrepreneur Naftali Bennett, which is expected to more than quadruple its current three mandates to become the third largest party in the parliament. The Labour Party is expected to come in second with around 16 mandates.

Under Israeli law, campaigning must end Monday at 7 p.m. (1700 GMT), 12 hours before the polling stations open.

Meanwhile, the first Israeli soldiers had began voting already on Saturday, using an army ballot box in a military base in Tel Aviv. Other members of the armed forces were casting their ballots on Sunday and Monday.

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