BREAKING NEWS: U.S. and Israel are striking Iran, sources tell NBC News

Washington, DC (NBC News) -- Israel has launched what it called a preemptive strike against Iran

“The State of Israel has launched a preemptive strike against Iran to remove threats against the State of Israel,” a spokesperson for Israel’s defense minister said.

Retaliation is expected, the spokesperson said.

“As a result, a missile and UAV attack against the State of Israel and its civilian population is expected in the immediate time frame,” the spokesperson said.

What to know:

The U.S. built up a massive military presence in the Middle East while holding talks with the Islamic Republic over a new deal to curtail its nuclear program.

The United States and Israel have launched strikes against Iran, according to a U.S. official.

Iran’s semi-official FARS news agency reported that explosions had been heard across Tehran.

After starting what Israel called a "preemptive strike," an Israeli spokesperson said retaliation was expected and Israel has declared a state of emergency.

Iran has vowed that if attacked it would retaliate against American and Israeli bases in the region, warning of a “devastating war.”