Israel-Gaza updates: IDF says officer and soldier injured in attack from Lebanon

The U.S. embassy in Beirut has issued a warning to U.S. citizens in Lebanon "who wish to depart Lebanon to book any ticket available to them." The embassy warned those who choose not to leave to "prepare contingency plans for emergency situations and be prepared to shelter in place for an extended period of time."

"The U.S. Embassy notes several airlines have suspended or cancelled flights, and many flights have sold out; however, commercial transportation options to leave Lebanon remain available. Please see available flight options at Beirut–Rafic Hariri International Airport," the embassy said.

"U.S. citizens who lack funds to return to the United States may contact the embassy for financial assistance via repatriation loans," the embassy said.

At least 10 Palestinians have been killed after the Israeli Defense Forces conducted an airstrike on a school in Gaza City on Saturday, claiming it was being used as a "command and control" center by Hamas.

Gaza civil defense said they are having trouble reaching victims because of continuing bombardment of the school.

U.S. Defense Secretary Lloyd Austin will direct "multiple" force posture changes in the Middle East to protect U.S. troops and help defend Israel, Pentagon deputy press secretary Sabrina Singh said during a briefing Friday.

"As we've demonstrated since October and again in April, the United States' global defense is dynamic, and the department retains the capability to deploy on short notice to meet evolving national security threats," Singh said.

"As a result, the secretary will be directing multiple forthcoming force posture moves to bolster force protection for U.S. forces region wide, to provide elevated support to the defense of Israel, and to ensure the United States is prepared to respond to this evolving crisis. In terms of what specifics that means, I don't have that for you right now," Singh said.

When asked for details on when and what types of forces would be moved where, Singh said these will be decided by Austin, implying that specific orders have not yet been issued.

-ABC News' Matt Seyler

An outbreak of 40,000 cases of hepatitis A have been recorded in the Gaza Strip amid the collapse of the waste management system as Israel continues its offensive there, according to the United Nations Relief and Works Agency for Palestine Refugees in the Near East.

The outbreak is a surge in cases -- which include children -- compared to only 85 recorded cases of hepatitis before the war began.

Hepatitis A is a disease of the liver that usually causes a mild, short-term illness, according to the Centers for Disease Control and Prevention. The hepatitis virus is contagious and spreads through close person-to-person contact and eating contaminated food or drink.

Vaccination is the best way to prevent infection, according to the CDC.