AMSTERDAM: Israeli President Shimon Peres says ''all options'' are being kept open in forcing Iran to give up its nuclear program, which Iran says is for peaceful purposes but Israel and others believe is aimed at building nuclear arms.

He said the economic sanctions against Iran now have not dissuaded the country from enriching uranium or building long-range missiles, although it may have affected Tehran's public statements.

Peres said it would be better if sanctions did stop Iran from being ''a centre of terror, but all options are otherwise being kept.''

''The Syrians were forced this time by an agreement between the United States and Russia to give up their chemical arsenal,'' he said. ''They didn't do it before the world threatened them with the military option.''

Peres spoke at the Peace Palace in The Hague after meeting with judges at the International Court of Justice, sometimes called the World Court, on Monday. The ICJ ruled in 2004 in a nonbinding advisory opinion that Israel's security barrier violated international law. Israel rejected the opinion.

Asked whether Israel would be willing to join the Organization for the Prohibition for Chemical Weapons as Syria is now doing, Peres said his government, which is widely believed to possess chemical weapons, ''will consider'' it.

Israel has signed but not ratified the Chemical Weapons Convention, which forbids the production, stockpiling or use of chemical weapons and automatically leads to membership in the OPCW.

After Syria's agreement last week to join the organization, only Israel, Egypt, North Korea, Burma, Angola and South Sudan are not members.

On Friday, the U.N. Security Council ordered the Organization for the Prohibition of Chemical Weapons to help Syria destroy its chemical weapons by mid-2014. Inspectors from the OPCW were leaving the Netherlands on Monday for Syria to begin the process.

Asked what he thought of the speech by Iran's new President Hassan Rouhani to the United Nations last week in which Rouhani argued Iran's nuclear program is purely civilian, Peres told reporters it contradicted a speech the Iranian leader gave just two days earlier to Iran's Revolutionary Guard. In that, Rouhani vowed to continue building long-range missiles.

Peres said those missiles could have no purpose other than to carry nuclear warheads, so the two speeches were contradictory.

''I hope that the facts will justify the hopes of many that we will see a different Iran, but finally we can judge only by the acts and by the deeds,'' he said.

Israeli Prime Minister Benjamin Netanyahu is due to meet with President Barack Obama later Monday in Washington and discuss relations with Iran.