Israel on Thursday said humanitarian aid was continuing to enter the Gaza Strip and urged Hamas to uphold its side of the ceasefire deal and return the remains of the deceased hostages it holds.

Since Monday’s exchange, Hamas has returned 10 bodies, nine of which Israel’s military has identified as hostages. Israel said there were 28 total in Gaza before the exchange.

A Hamas official said on Thursday that the group is facing difficulties in recovering the bodies of Israeli hostages held in Gaza, saying some are underneath rubble that must be cleared with heavy equipment.

Hamas representative in Lebanon Ahmad Abdul-Hadi said Hamas is committed to the US-brokered ceasefire agreement reached earlier this month adding that there are difficulties in search operations and finding the bodies.

AP video and production by Fadi Altawil