The top U.S. diplomat’s visit to the region came as humanitarian conditions rapidly deteriorated in the Palestinian enclave.

Israeli soldiers sit in a military vehicle near trucks carrying humanitarian aid that wait before making their way to the Gaza Strip, amid the ongoing conflict in Gaza between Israel and Hamas, at Erez Crossing in southern Israel,

The first aid in two weeks was allowed into northern Gaza following the letter, but the UN's acting humanitarian chief Joyce Msuya described it as a “trickle”. In the letter sent on Sunday, the US expressed deep concern at the humanitarian situation and said Israeli actions had contributed to it.