NBC News' Matt Bradley reports from Israel where sirens rang out across Tel Aviv after missiles were reportedly launched from Iran. The order for residents to take cover was lifted about 15 minutes later.

The Iran-Israel conflict has shuttered airspace across the Middle East as the two bitter enemies launch attacks and reprisals at one another.

NBC's Matt Bradley said Monday night was "quite a bit less terrifying" than Friday, Saturday or Sunday, and the Iranians could be "running out of steam." "According to the IDF, last night was the lightest Iranian assault on Israel since this all began with Israel’s attacks against Iran on Friday morning,

At least seven people were killed and more than 100 injured when an Iranian ballistic missile hit Bat Yam, just south of Tel Aviv, overnight on Sunday, domestic media reported. Other reports put the death toll at six people. Israel's police said residential buildings took a "direct hit that caused extensive damage."

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.

A rare daytime missile barrage on Tel Aviv forces millions into shelters as Israeli forces retaliate against Iran's missile-launching capabilities.

Both countries have closed their airspaces, leaving few options for citizens of other countries seeking to leave.