NEW YORK: US President Barack Obama on Tuesday warned that he remained ready to use force over Syria’s chemical weapons as he demanded that the United Nations take action.

In a sometimes defensive speech at the UN General Assembly, Obama said the United States was ready to defend interests in the Middle East including ensuring “free flow of energy” and prohibiting weapons of mass destruction.

“The United States of America is prepared to use all elements of our power, including military force, to secure these core interests in the region,” Obama told world leaders.

Obama said that the world’s credibility was at stake after Syrian President Bashar Assad’s alleged use of chemical weapons.

“There must be a strong (UN) Security Council resolution to verify that the Assad regime is keeping its commitments, and there must be consequences if they fail to do so,” Obama said.

“If we cannot agree even on this, then it will show that the UN is incapable of enforcing the most basic of international laws.

“On the other hand, if we succeed, it will send a powerful message that the use of chemical weapons has no place in the 21st century, and that this body means what it says,” he said.

Obama lashed out at critics who questioned whether Assad carried out the Aug. 21 chemical attack near Damascus, which US intelligence says killed some 1,400 people.

“These rockets were fired from a regime-controlled neighborhood and landed in opposition neighborhoods,” Obama said.

“It is an insult to human reason — and to the legitimacy of this institution — to suggest that anyone other than the regime carried out this attack,” he said.

Obama said he is ready to test a difficult “diplomatic path” to better relations with Iran while pressing for an end to its nuclear drive.

Speaking just ahead of Iran’s new President Hassan Rowhani, Obama devoted much of his speech to the UN summit to overtures to the new Tehran leadership.

Obama said “Iran’s pursuit of nuclear weapons” would remain a US foreign policy priority and stressed that “mistrust has deep roots” between the United States and Iran.

But he added that a “meaningful agreement” between the arch-rivals is possible.