UNITED NATIONS, Feb. 20 (Xinhua) -- The United Nations is very concerned about the situation surrounding Iran, Stephane Dujarric, spokesperson for the UN secretary-general, said Friday.

"I can tell you and reiterate yet again that we are very concerned about the heightened rhetoric we're seeing around the region, by the heightened military activities, war games, or just increased military naval presence in the region," Dujarric said at a daily briefing in response to a question posed by Xinhua about a letter the Iranian permanent mission sent to the UN chief and the president of the Security Council on Thursday.

"And we encourage both the United States and the Islamic Republic of Iran to continue to engage in diplomacy in order to settle the differences," he said.

In the letter, Iran's UN ambassador Amir Saeid Iravani said the country will respond "decisively and proportionately" to any military aggression, exercising its right to self-defense under the UN Charter, and urged the Security Council and the UN secretary-general to "act without delay, before it is too late."

According to Dujarric, the letter has gone to the Security Council and to the General Assembly, as requested by Iran's permanent mission to the United Nations. ■