2 dead after Israel targets senior Hezbollah commander Fouad ...

Two people are dead and 20 others were injured after Israel launched a strike on Beirut, the capital city of Lebanon, on Tuesday that targeted a senior Hezbollah commander as tensions along Israel's northern border continue to escalate.

The strike hit a residential building in Haret Hreik, according to the Lebanese Red Cross.

Fouad Shukr, also known as Al-Hajj Mohsen, was targeted in the strike, according to three security sources familiar with the operation. Shukr is a senior adviser on military affairs to Hasan Nasrallah, secretary-general of Hezbollah. He also had a $5 million reward for information leading to his capture, via the U.S. government.

The IDF claimed that Shukr was killed in the strike.

"The IDF targeted in Beirut the commander responsible for the murder of the children in Majdal Shams and killed many Israeli civilians," the Israel Defense Forces told ABC News in a statement.

"Hezbollah crossed the red line," Israeli Defense Minister Yoav Gallant said on social media.

Israel struck Dahiya, a district in Beirut’s southern suburbs that is a stronghold of militant group Hezbollah.

Twelve people, including children playing soccer, were killed in a strike on the Golan Heights over the weekend. Hezbollah denied responsibility, but both the U.S. and Israel have said the missile used in the attack came from a Hezbollah-controlled location.

"This attack was conducted by Lebanese Hezbollah," White House National Security Council spokesperson Adrienne Watson said in a statement Sunday. "It was their rocket, and launched from an area they control. It should be universally condemned."

In recent days, Hezbollah has said that any strike in Beirut would be met with a strong response of their own.

Lebanese Caretaker Prime Minister Najib Mikati said the area struck was meters away from one of the largest hospitals in Lebanon and said they reserve the right to respond to Israel's attack.

"This criminal act that occurred tonight is a link in a series of aggressive operations that are claiming civilians in a clear and frank violation of International law and international humanitarian law, which is something we put in place for the international community, which must bear its responsibilities and press with all force to oblige Israel to stop its aggression and threats and implement international resolutions," Mikati said Tuesday.

The U.S. was given advanced notice ahead of Israel’s strike in Beirut, according to a U.S. official familiar with matter. The message was communicated via security channels and limited operational detail was shared, the official said.

It’s still unclear whether the strike successfully eliminated its target, and assessments are ongoing, according to the U.S. official.

U.S. State Department deputy spokesperson Vedant Pate said earlier that the U.S. has been in "continuous discussions with Israeli and Lebanese counterparts" since the weekend.

"The United States is going to continue to support efforts to reach a diplomatic solution along the blue line," Pate said.

"Our support for Israel's security is ironclad, and it's unwavering, especially as it defends itself against Iran backed threats, including threats from Hezbollah," Pate told reporters.

ABC News' Shannon K. Kingston contributed to this report.