The U.S. government asked Japan to suspend Foreign Minister Hirofumi Nakasone's recent trip to Iran due to President Mahmoud Ahmadinejad's remarks on Israel, informed sources said Sunday.

Despite the request, Nakasone met Ahmadinejad in Tehran on May 2 and called on the Iranian leader to give humanitarian consideration to the case of an American journalist of Japanese descent then being detained in Iran for espionage.

"It was not a strong request (from the U.S. side)," a Japanese source said. "And we have not seen any actual problems over the issue."

Responding to the U.S. request made through diplomatic channels, Japan sought understanding by explaining that Nakasone would refer to the issue of the American journalist.

In his speech to an international conference against racism in Geneva last month, the Iranian president called Israel "racist," prompting European diplomats to walk out of the session.