At least four people were killed and 40 others wounded Monday in an Israeli airstrike on tents housing displaced Palestinians inside the Al-Aqsa Hospital in the central Gaza's city of Deir al-Balah, health officials said.

The Israeli military said it targeted militants operating from a command center inside the compound. Israel accuses Hamas of routine use of civilian facilities such as hospitals for military purposes -- a charge Hamas denies.

-ABC News' Will Gretsky

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