Israel’s attack on Iran was long in the making – the result of years of meticulous planning by Israel and days of high-stakes talks between Tel Aviv and Washington, officials told CNN.

Three people have been killed in Israel, according to officials and local media, with both sides saying the strikes will continue.

Israel’s leader and President Trump appeared to bet they can persevere, but other world leaders warned of unintended outcomes in a volatile region.

VATICAN CITY (Reuters) -Pope Leo appealed on Saturday for authorities in Iran and Israel to act with "reason" after recent airstrikes and to pursue dialogue. He told an audience in St. Peter's Basilica he was following the situation with "great concern."

Iran's strikes against Israel will continue, with targets set to expand to include U.S. bases in the region in the coming days, Iran's Fars news agency reported on Saturday, citing senior Iranian military officials.

Israel sent 200 fighter jets to conduct its operation in Iran and has dropped more than 330 different types of munitions so far, Israeli military spokesman Effie Defrin said.

Israeli emergency services have said at least two people were killed in the strikes and dozens of people are injured.