TOKYO (IRNA) -- Former UN nuclear watchdog chief Hans Blix says direct Tehran-Washington talks is the key to resolving Iran's nuclear program.

"As was the case with North Korea, the key to Iran's nuclear issue is whether the U.S. would go into direct talks with Iranian government or not," said Blix in an interview with Japanese daily Mainichi.

Blix said the difference between nuclear program of Iran and of North Korea is that agreement on North Korea's nuclear issue was reached within the framework of six-party talks but this was not so in Iran's case and the UN Security Council in the first step issued a resolution against Tehran.

He added that unconditional talks is the most prudent way of promoting talks and would be less insulting to the other party.

He added that unconditional talks was the key to agreement in the six-party talks.