The U.S. Department of Defense said on Sunday that Defense Secretary Lloyd Austin ordered a guided missile submarine to be sent to the Middle East and requested the aircraft carrier USS Abraham Lincoln to sail to the region more quickly.

These steps come as the United States and other allies push Israel and Hamas to reach a ceasefire agreement that could help ease rising 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 monitoring retaliatory strikes by both Iran and Hezbollah in response to the killings, and the United States has been bolstering its presence in the region.

Major General Pat Ryder, the Pentagon's press secretary, stated in a statement that Austin spoke with Israeli Defense Minister Yoav Gallant earlier in the day, reaffirming America's commitment to "taking every possible step to defend Israel" and noted the strengthening of the position and capabilities of U.S. military forces throughout the Middle East in light of escalating regional tensions.

Orders have already been given for Lincoln, which was in the Asia-Pacific region, to head to the area to replace the aircraft carrier USS Theodore Roosevelt, which is set to begin returning home from the Middle East. Last week, Austin said Lincoln would arrive in the Central Command area by the end of the month.

It was unclear on Sunday what the latest order meant, or how quickly Lincoln would sail to the Middle East. The aircraft carrier carries F-35 fighter jets onboard, along with F/A-18 fighters that are also present on the carriers.

Ryder did not mention how quickly the guided missile submarine USS Georgia would reach the region.

He said Austin and Gallant also discussed Israeli military operations in Gaza and the importance of mitigating harm to civilians.

This call comes a day after an Israeli airstrike on a school turned shelter in Gaza early Saturday, resulting in at least 80 deaths and nearly 50 injuries, according to Palestinian health authorities, in one of the deadliest attacks in the ten-month-long war between Israel and Hamas.