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

Smoke and missiles have lit up the skies in Israel and Iran in a fierce standoff triggered by fears over Tehran’s expanding nuclear program. Since June 13, hundreds of military strikes have been exchanged as the two nations remain locked in a conflict that shows no signs of abating.

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.

Delta Air Lines Inc. and United Airlines Holdings Inc. suspended flights to Tel Aviv following Israel’s bombing of Iran and the closure of Israel’s airspace.