Iranian President Mahmoud Ahmadinejad has penned a letter to President Obama, telling his American counterpart that Iran is Obama's only option for success, state-run media reported.

"Obama has only one way to remain in power and be successful. This way is Iran," Ahmadinejad said in a nationally televised speech this week, according to the Iranian Republic News Agency (IRNA).

"Obama should start cooperation with Iran in practice," he said. "I have written a letter to Obama which will be published soon."

Ahmadinejad spoke just days after the conclusion of a 47-nation nuclear summit convened by Obama to raise global awareness of the threat of nuclear terrorism.

The White House has been pressing for a fourth round of United Nations sanctions on Iran for its nuclear ambitions. Iran says its nuclear programs are designed for civilian use.

"The time when they imagine that they can do any harm on Iran is over," Ahmadinejad said, according to IRNA.

To read full CNN story — Go Here Now.