Israel has issued an "urgent warning to Iranian citizens" to evacuate areas close to military sites after fresh exchanges of strikes between the two countries overnight raised fears of further escalation.

Smoke and flames filled the sky over Tehran as Israel struck oil and gas facilities in the Iranian capital and targeted more nuclear facilities during attacks that carried on into Sunday after starting two days earlier.

The strikes came after the Israeli military said it had carried out fresh strikes on Iran nuclear infrastructure sites.

Iran launched dozens of ballistic missiles toward Israel on Friday night in retaliation for Israel's surprise attack early Friday. Israel struck at the heart of the Iran's nuclear program, killing several nuclear scientists as well as high-ranking military leaders, according to Israeli officials.

Cypriot President Nikos Christodoulides said he would speak with Israeli Prime Minister Benjamin Netanyahu on Sunday to convey a message from Iran, as the clash between the countries enters its third day.

Israel’s unprecedented attacks on Iran had at their core an elusive and high-risk goal: eradicating the country’s controversial nuclear program.

Maj. Gen. Yadlin, who flew in the 1981 Osirak reactor strike, explains why Israel's current operation against Iran represents a complex, multi-week campaign.