U.S. Defense Secretary Lloyd Austin has ordered a guided missile submarine to the Middle East and is telling the USS Abraham Lincoln aircraft carrier strike group to sail more quickly to the area, the Defense Department said Sunday.

The moves come as the U.S. and other allies push for Israel and Hamas to achieve a cease-fire agreement that could help calm soaring tensions in the region following the assassination of Hamas political leader Ismail Haniyeh in Tehran and a senior Hezbollah commander in Beirut.

Officials have been on the lookout for retaliatory strikes by both Iran and Hezbollah for the killings, and the U.S. has been beefing up its presence in the region.

Maj. Gen. Pat Ryder, Pentagon press secretary, said in a statement that Austin spoke with Israeli Defense Minister Yoav Gallant earlier in the day, and reiterated America's commitment "to take every possible step to defend Israel and noted the strengthening of U.S. military force posture and capabilities throughout the Middle East in light of escalating regional tensions."

The Lincoln, which has been in the Asia Pacific, had already been ordered to the region to replace the USS Theodore Roosevelt aircraft carrier strike group, which is scheduled to begin heading home from the Middle East. Last week, Austin said the Lincoln would arrive in the Central Command area by the end of the month.

It wasn't clear Sunday what his latest order means, or how much more quickly the Lincoln will steam to the Middle East. The carrier has F-35 fighter jets aboard, along with the F/A-18 fighter aircraft that are also on carriers.

Ryder also did not say how quickly the USS Georgia guided missile submarine would get to the region.

He said Austin and Gallant also discussed Israel's military operations in Gaza and the importance of mitigating civilian harm.

The call comes a day after an Israeli airstrike hit a school-turned-shelter in Gaza early Saturday, killing at least 80 people and wounding nearly 50 others, Palestinian health authorities said, in one of the deadliest attacks of the 10-month Israel-Hamas war.