JERUSALEM - Israel's recently retired spy chief says more time and efforts are needed before considering a military strike on Iran.

Meir Dagan, who served as Mossad's head from 2002 to 2010, told CBS's 60 Minutes that he believes Tehran is being "rational" and "very careful" now, and is considering the consequences of continuing the country's controversial nuclear program.

Dagan also says world powers should assist opposition groups in Iran to foment regime change. He would not say if Israel supported protest groups against the regime in the past.

Mossad is thought to have played a role in the assassinations of Iranian nuclear scientists and computer viruses that disrupted Iranian research facilities.

CBS released excerpts from the interview on Thursday.