The United Nations Children's Fund (UNICEF) said at least 322 children had been killed and 609 injured since the breakdown of the ceasefire and the Israeli military's resumption of bombardments in Gaza on March 18.
"Most of these children were displaced, sheltering in makeshift tents or damaged homes," UNICEF said in a statement.
The agency went on to say that the "resurgence of relentless and indiscriminate bombardments" coupled with three weeks of a "complete block on supplies entering Gaza" had put the humanitarian response under severe strain.
US military announces more air assets for Middle East
The United States has ordered the deployment of additional warplanes to the Middle East.
"Additional squadrons and other air assets" will reinforce US warships in the Middle East, said a defense department statement released on Tuesday.
The move comes amid a US bombing campaign targeting Iranian-backed Houthis in Yemen, which saw more air attacks early Tuesday morning.
It also comes as US President Donald Trump increases threats on Iran to curb its nuclear program.
"The United States and its partners remain committed to regional security in the CENTCOM (area of responsibility) and are prepared to respond to any state or non-state actor seeking to broaden or escalate conflict in the region," Pentagon spokesperson Sean Parnell said in the statement.
CENTCOM refers to the US Central Command, which comprises a region stretching across northeast Africa, the Middle East and Central and South Asia.
What military planes are the US sending to Middle East?
The Pentagon's statement made no mention of specific aircraft.
However, at least four B-2 stealth bombers were relocated last week to a US-British military base on the tiny Indian Ocean island of Diego Garcia in the Chagos archipelago, according to according to US officials, speaking on condition of anonymity, and reported on by Reuters.
The B-2 bombers are capable of carrying nuclear weapons and, with only 20 such aircraft in the Air Force's inventory, are usually used sparingly.