(JTA) — This is a developing story and will be updated.

Israel announced that it has conducted a military strike on Iran and has warned Israelis to prepare for a potential counterattack.

“Following the State of Israel’s preemptive strike against Iran, a missile and drone attack against the State of Israel and its civilian population is expected in the immediate future,” Defense Minister Israel Katz said in a statement. Sirens blared across the country, telling Israelis to seek shelter.

The development came early Friday morning Israel time and followed several days of increasing tensions, during which the United States pulled some personnel out of the region and U.S. President Donald Trump told Israeli Prime Minister Benjamin Netanyahu not to strike.

Trump’s top negotiator who is working to strike a nuclear deal with Iran, Steve Witkoff, reportedly warned Senate Republicans last week that an Iranian response to an Israeli strike could result in mass civilian casualties in Israel.

Last year, Israel struck military facilities within Iran and Iran responded with a barrage of missiles that Israel mostly shot down with the help of its allies, including the United States.

Walla, an Israeli online news site, reported on Thursday evening that the Trump administration relayed to Netanyahu that it would not directly assist Israel in an attack on Iran. It was not clear if indirect assistance, such as refueling planes, was off the table, said the news site, which quoted two American officials.