UN relief chief Tom Fletcher said that Hamas must make strenuous efforts to return all the bodies of deceased hostages, and that Israel must allow the massive surge of humanitarian aid on which so many lives depend.

UNITED NATIONS, Oct. 15 (Xinhua) -- The planned scale-up in humanitarian aid deliveries in the Gaza Strip has suffered a setback since the ceasefire deal took effect, UN relief chief Tom Fletcher said Wednesday.

"We must not fail to see through in full the implementation of the agreements made," said Fletcher, also UN under-secretary-general. "Earlier this week, we were able to kick off our humanitarian scale-up after months of frustration and blockages. Food, medicine, fuel, water, cooking gas and tents got through to those who need them. We made progress clearing roads and reopening bakeries. We shared in the joy and relief of families reunited."

Israel on Tuesday announced that it was cutting half the number of truckloads carrying aid allowed into Gaza, or by about 300 truckloads.

The Israeli authorities claimed that the capping was triggered by the failure of Hamas to deliver the remains of deceased hostages.

The UN relief coordinator said that Hamas must make strenuous efforts to return all the bodies of deceased hostages, and that Israel must allow the massive surge of humanitarian aid on which so many lives depend.

Fletcher said that the humanitarian community is determined to save lives, whatever the obstacles.

"We will not accept any interference with our aid distribution," he added.

The UN Office for the Coordination of Humanitarian Affairs (OCHA), which Fletcher leads, said that humanitarian efforts on the ground continued for Gaza.

OCHA said its partners support the production or delivery of hundreds of thousands of meals and bread bundles every day.

The office said that on Monday, the Israeli sides of the Kerem Shalom/Karem Abu Salem and Kissufim border crossings were closed for the exchange of Israeli hostages and Palestinian detainees. No cargo could be offloaded, and only limited supplies, previously cleared through the crossings, could be collected on the Gaza side.

It added that on Tuesday, both crossings remained closed to humanitarian supplies from the Israeli side. However, the United Nations and its partners were able to collect previously cleared cargo from the Gaza side to support health, water, hygiene, sanitation and food operations.

According to the office, all seven humanitarian missions requesting coordination with the Israeli authorities were facilitated on Tuesday, with only one impeded on the ground, before it was eventually accomplished.

The coordinated movements allowed teams to collect supplies from crossings and advance the clearance of the road to Zikim crossing in the north, in anticipation of its opening.

"We're all trying to live with this new situation, and we're trying to find ways to severely increase the aid that goes in through more crossings with more volume," Stephane Dujarric, chief spokesman for the UN Secretary-General, told a daily briefing.