Defense Secretary Robert Gates reassured Israelis that the offer to talk to Tehran isn't open-ended, but some caution that Obama's basic policy on the issue has not changed.
Growing unease over conditions of detention for hundreds is helping opposition organize, and exposing some splits in Iran's conservative ranks.
President Mahmoud Ahmadinejad fired his intelligence minister Sunday after being forced to remove his first vice president, a close adviser.
In Syria, Mitchell said peace between Israel and Syria was a 'near-term goal.' Syrian, Israeli, Egyptian, and Palestinian leaders are meeting with the special envoy, who will be joined by Defense Secretary Gates and other high-level US officials.
The highly touted Arrow 2 is considered central to Israel's defense against an unconventional attack.