The State Department raised its travel advisory for Israel to Level 4, the highest level, amid airstrikes from Iran.

The conflict between Israel and Iran has forced many countries in the Middle East to close their airspace, as Israeli jets and Iranian exploding drones and missiles fly over their night skies.

Aerial attacks between Israel and Iran continued overnight into Monday, marking a fourth day of strikes following Israel's Friday attack. That surprise strike hit the heart of Iran's nuclear program, killing several nuclear scientists as well as high-ranking military leaders, according to Israeli officials.

Onlookers gathered on Saturday at a central Tel Aviv residential building next door to Israel’s defense headquarters that was damaged after it took a hit from what appeared to be shrapnel from an overnight missile barrage from Iran.

Israeli citizens were ordered to head to bomb shelters on Friday night amid retaliatory missile strikes from Iran.

Video verified by CNN captures the dramatic moment a missile struck in vicinity of the Kirya, an area of Tel Aviv that’s home to an urban military base housing Israel’s Defense Forces.

Residents awoke to mostly quiet streets in Tel Aviv after spending the night running back and forth to bomb shelters after Iran’s attacks on the coastal city. Some restaurants and cafes were closed, although those that remained open were full of people drinking coffee and eating pastries as normal.

Iran and Israel targeted each other with airstrikes early on Saturday after Israel launched its biggest-ever offensive against its longtime foe in a bid to prevent it from developing a nuclear weapon.