UNITED NATIONS—Airstrikes by the U.S. and a group of Arab allies against Islamic State targets in Syria are illegal and constitute an attack on the country, Hassan Rouhani, the president of Iran, said Tuesday.
Mr. Rouhani said military action could only be justified if authorized by the United Nations Security Council or if the measures were conducted with the consent of the Syrian government.
"These bombings do not have any legal standing so we can interpret them as an attack," he told journalists on the fringes of the United Nations General Assembly.
Mr. Rouhani condemned Islamic State and described them as "barbarians," but said Iran should lead any coalition in the fight against the group that has seized control of swaths of Syrian and Iraqi territory.
The Iranian president seemed eager to express Iran's willingness to combat the militant group, but he signaled no willingness to work with the U.S. government in the task.
"There is no cooperation between Iran and the United States but we are extremely serious about combating extremism."
Iran has been a long-standing ally of Syrian President Bashar al-Assad and Mr. Rouhani noted that Iran has been fighting Islamic State extremists in the region alongside Syrian forces.
Also, Mr. Rouhani expressed optimism that a final deal on Iran's nuclear program with the U.S., Russia, China, the U.K., France and Germany could be reached before the deadline set in an interim agreement earlier this year.
"There are still differences between the two sides but I do believe in the next two months we can reach an agreement."
The continuing differences go beyond the issue of the number of centrifuges Iran will be allowed to continue operating, he said, and included disagreements over the time-frame of the agreement and over how it will be executed.
Mr. Rouhani added that this week would be an important one in the nuclear talks. He is scheduled to address the U.N. General Assembly later this week and is expected to hold meetings with diplomats from various countries, though he won't meet PresidentBarack Obama when he visits the U.N. tomorrow.