U.S. Defense Secretary Lloyd Austin spoke with Israeli Minister of Defense Yoav Gallant by phone on Sunday to express his condolences for the IDF soldiers killed in a Hezbollah drone attack and discuss the IDF's military operations in Lebanon.

According to a readout of the call from the Pentagon, Austin, "reinforced the importance of Israel taking all necessary measures to ensure the safety and security of UNIFIL forces and Lebanese Armed Forces, and the need to pivot from military operations in Lebanon to a diplomatic pathway to provide security for civilians on both sides of the border as soon as feasible."

The United Nations Interim Force in Lebanon (UNIFIL) is a peacekeeping mission in Lebanon established by the U.N. Security Council.

The conversation comes after the IDF has repeatedly fired on the UNIFIL headquarters in southern Lebanon.

Additionally, Secretary Austin "reaffirmed the deep U.S. commitment to Israel’s security," which he says is demonstrated by the deployment of the U.S. Terminal High Altitude Area Defense (THAAD).

According to the Department of Defense, THAAD employs interceptor missiles, using “hit-to-kill” technology, to destroy threat missiles.

During the call, Austin "again raised concern for the dire humanitarian situation in Gaza and stressed that steps must be taken soon to address it," the Pentagon said.

At least three people were killed and dozens more were injured after Israel Defense Forces struck Al Aqsa Hospital in Gaza on Sunday.

-ABC News' Will Gretsky

The Israel Defense Forces said Hezbollah struck one of its bases Sunday, killing at least four soldiers.

Another seven soldiers were "severely injured," according to the IDF statement.

"The IDF shares in the grief of the bereaved families and will continue to accompany them," the IDF said.

At least 22 people were killed after the Israel Defense Forces shelled a school housing displaced people in the Al-Mufti area, north of Nuseirat, in the central Gaza Strip, the Gaza Health Ministry said Sunday.

Among the deceased were 15 women and children, officials said, and at least 80 others were injured.

-ABC News' Will Gretsky

U.N. peacekeeping troops claimed Israel Defense Forces tanks destroyed the main gate of their base in Ramyah in southern Lebanon on Sunday, breached the facility and stayed for 45 minutes.

The two IDF Merkava tanks left the base after the U.N. Interim Force in Lebanon (UNIFIL) protested the action through a "liaison mechanism," according to U.N. officials.

Two hours later, U.N. peacekeepers at the Ramyah position reported hearing "several rounds" fired nearby. Smoke from the rounds, according to UNIFIL, engulfed the base, causing 15 peacekeepers to be treated for "skin irritation and gastrointestinal reactions" and other effects.

IDF soldiers, according to UNIFIL, also stopped a "critical UNIFIL logistical movement" near Meiss ej Jabel on Saturday, denying it passage. The critical movement could not be completed, UNIFIL said in a statement.

The statement called on the IDF to respect the safety of U.N. personnel, saying, that UNIFIL has requested "an explanation from the IDF from these shocking violations."

There was no immediate response from the IDF.

"Breaching and entering a U.N. position is a further flagrant violation of international law and Security Council resolution 1701 (2006)," UNIFIL said in its statement. "Any deliberate attack on peacekeepers is a grave violation of international humanitarian law and resolution 1701. UNIFIL’s mandate provides for its freedom of movement in its area of operations, and any restriction on this is a violation of resolution 1701."

-ABC News' Ghazi Balkiz and Victoria Beaulé