After days of sharp debate at the top levels of government, Iran’s senior military commanders prevailed, and almost 200 ballistic missiles were sent speeding toward the heart of Israel.

The direct military strike on Tuesday came after senior military commanders of the Revolutionary Guards Corps convinced the country’s supreme leader, Ayatollah Ali Khamenei, that it was the only course of action if Iran wanted to appear strong, according to three Iranian officials.

During the surprise attack, Iran launched about 180 ballistic missiles at Israel, the Israel military said. Some landed, but most were intercepted, Israel said.

But the Iranian military has also prepared hundreds of missiles to launch from western borders should Israel or its top ally, the United States, strike back, two members of the Revolutionary Guards familiar with the planning said.

”If the Zionist regime reacts to Iran’s operation it will face more fierce attacks,” said the Revolutionary Guards said in a statement

The statement said the missiles had been launched to retaliate for Israel’s assassination last week of Hassan Nasrallah, leader of Hezbollah, the Lebanese militant group. Mr. Nasrallah was the most powerful figure in Iran’s “axis of resistance” — how it refers to its regional alliance of militants — and a close confidant of Mr. Khamenei.