U.S. President Barack Obama said on Saturday that his administration still seeks dialogue with Iran over its nuclear issue but the Iran government has chosen isolation.

Obama made the remarks in a special video message in celebration of Nowruz, or "New Day," which marks the arrival of spring and the beginning of the New Year for millions in Iran and other communities around the world.

"We are working with the international community to hold the Iranian government accountable because they refuse to live up to their international obligations," Obama said in the message.

"But our offer of comprehensive diplomatic contacts and dialogue stands," Obama stressed.

The U.S. president accused Tehran of having chosen to isolate itself and focus on the past over a commitment to build a better future.

Despite its differences with Tehran, Obama said, the United States is still committed to helping build a better future for the Iranians.

"Even as we continue to have differences with the Iranian government, we will sustain our commitment to a more hopeful future for the Iranian people," he said.

Obama delivered a similar video message on the occasion of Nowruz last year in which he said his administration sought "the promise of a new beginning" in its relationship with Iran.

The United States has been accusing Tehran of attempting to build nuclear weapons. Tehran has rejected the accusation and insisted that the Islamic republic has the right to use nuclear energy for peaceful purpose.

Over the past few months, the Obama administration has pledged to pursue tough sanctions against Iran in a bid to prevent the Islamic republic from acquiring nuclear weapons.