As the clash intensified, American Airlines, United Airlines and Delta Air Lines have suspended flights to Israel.

Reports said Israeli airstrikes hit Gaza, while Palestinian Izz ad-Din al-Qassam Brigades in Gaza fired a rocket at targets in Israel, including the airport in Tel Aviv.

The rocket was launched in response to the killing of its senior commanders, said reports.

Earlier on Wednesday morning, rockets were fired also toward Israel's international Ben Gurion Airport outside Tel Aviv, where all flights have been halted since Tuesday, the Airports Authority said in a statement.

Before dawn, Israeli war jets struck a building which the army said was used by operatives with the Hamas' military-intelligence apparatus. According to a military statement, several operatives were killed including Hassan Kaogi, head of Hamas' Military Intelligence Security Department and his deputy, Wail Issa, head of the Military Intelligence Counter-Espionage Department.

The military's Home Front Command said in a statement that schools in a range spanning from southern Israel to Herzliya, a city north of Tel Aviv, are canceled for Wednesday.

Five people in Israel and at least 30 in Gaza were reported dead since Monday, in the worst flare-up since Israel's major military offensive in Gaza in 2014.