NBC News Chief Foreign Correspondent Richard Engel joins MSNBC's Lawrence O'Donnell to share the latest about what he's learning from his sources in Israel and Iran about the extent of the strikes by Israeli forces across Iran and how the Iranian government is likely to respond.

Channels in Iran associated with the Revolutionary Guards report explosions in Tehran. Defense Minister Israel Katz immediately declares a special state of emergency throughout the entire territory of the State of Israel.

"The commitment to building a safer world free from the nuclear threat must be pursued through respectful encounters and sincere dialogue," Leo said.

The Israeli Air Force conducted a strike in Iran on Thursday, according to two sources with knowledge of the operation. It's not yet clear what Israel is targeting. Why it matters: Israel is directly attacking its biggest and best-armed adversary,