The US President Barack Obama has called on the United Nations Security Council to approve a resolution that ensures Syria upholds its chemical weapons commitments.

The President, addressing the UN General Assembly, said a resolution must include consequences for President Bashar al-Assad's regime if he does not meet demands to dismantle his chemical stockpile.

Mr. Obama said failure to include such consequences would mean the international body is unable to enforce such requirements, and would be "an insult to human reason and the legitimacy" of the UN.

In an address focused primarily on the Middle East, the president also said a "diplomatic path must be tested" regarding Iran's nuclear programme.

Mr. Obama said he directed US Secretary of State John Kerry to pursue a possible nuclear weapons deal with Iran.

US President Obama (right) & Deputy UN Secretary-General Jan Eliasson

He said he has been encouraged by Iranian President Hasan Rouhani's more moderate course, but added Mr. Rouhani's "conciliatory words will have to be matched by actions that are transparent and verifiable".

The West has long suspected that Iran is seeking a nuclear weapon. Tehran has consistently denied the charge. It is still unclear if Mr. Obama will meet with the Iranian president while at the United Nations.

The leaders of the two countries have not had face-to-face contact in more than 30 years. US officials say no meeting is planned, although they have not ruled one out.

Mr. Obama also used his UN address to press for continued efforts in reaching a resolution of the long conflict between the Palestinians and the Israelis.

He said all sides must be willing to take risks in order to achieve Mideast peace, adding that Israel and its friends must be willing to accept a Palestinian state.

He also said Arab states must recognise that stability can only be achieved through a two-state solution with a secure Israel.