UNITED NATIONS: US President Barack Obama on Tuesday pushed for pursuing diplomacy with Iran's new government, but called on Tehran to be transparent about its nuclear program.

“The roadblocks may prove to be too great, but I firmly believe the diplomatic path must be tested,” Obama told the UN General Assembly, speaking just before Iranian President Hassan Rowhani was to address the annual summit.

Obama said he had instructed US Secretary of State John Kerry to pursue a possible new diplomatic opening with Tehran.

Kerry will meet Thursday with his new Iranian counterpart Mohammad Javad Zarif as well as foreign ministers from Britain, China, France, Germany and Russia at the United Nations headquarters.

It will be the first such minister-level talks on the nuclear issue since the negotiations were launched a decade ago.

But Obama stressed that Iran must take “transparent” and “verifiable”actions to end international suspicions over its nuclear program.

Iran's economy has been crippled by a series of UN and US sanctions aimed at crippling its nuclear program.

An offer by Western powers believed to lay out a softening of some of the sanctions in return for a halt to Tehran's uranium enrichment program has so far not gotten a response from Iran.

“Since I took office, I have made it clear - in letters to the Supreme Leader in Iran and more recently to President Rowhani - that America prefers to resolve our concerns over Iran's nuclear program peacefully, but that we are determined to prevent them from developing a nuclear weapon,” Obama said.

All eyes are watching to see if Obama will meet Rowhani on the sidelines of the annual meeting at the United Nations.

It would be a historic first since the 1979 revolution in Iran ousted the Shah and installed an Islamic republic.

“We are not seeking regime change, and we respect the right of the Iranian people to access peaceful nuclear energy,” Obama told the UN.

“Instead, we insist that the Iranian government meet its responsibilities under the Nuclear Non-Proliferation Treaty and UN Security Council resolutions.”

There are hopes that the new more moderate leadership which took office in August in Tehran may usher in an era of progress.

But Obama warned that “to succeed, conciliatory words will have to be matched by actions that are transparent and verifiable.”

”After all, it is the Iranian government's choices that have led to the comprehensive sanctions that are currently in place. This isn't simply an issue between America and Iran - the world has seen Iran evade its responsibilities in the past, and has an abiding interest in making sure that Iran meets its obligations in the future.”