Palestinian civilians in the Gaza Strip have sought shelter in an ever-shrinking area of the south as Israel stepped up its bombing from air, sea and land across the enclave, Reuters reports.

Bombardments were concentrated on Khan Younis and Rafah in the south, residents said. Hospitals were struggling to cope with the flow of wounded, they said.

The renewed warfare followed the collapse on Friday of a seven-day temporary pause in the fighting between Israeli forces and Hamas to allow an exchange of Israeli hostages and Palestinian prisoners.

It took place despite growing calls from the United States — Israel’s closest ally — for Israel to avoid further harm to Palestinian civilians.