tanker carrying oil docked at Hodeidah port in Yemen on Thursday -- the first such ship to berth this year in the country's Houthi-controlled north, where fuel is desperately needed to distribute food and to keep the country's hospitals from shuttering.

The arrival of the ship, the Gabon-registered Thuruya, follows a UN announcement on Wednesday that the internationally recognized government of Yemen -- supported by Saudi Arabia and its military -- had agreed to allow four ships carrying fuel to unload at Hodeidah. It was not clear if the relaxation was temporary or a permanent change.

A CNN investigation earlier this month revealed that Saudi warships were preventing all oil tankers from docking at the port, including 14 vessels that had gained approval from a United Nations clearance mechanism to berth. The investigation triggered calls from the UN Yemen Envoy Martin Griffiths and WFP Chief David Beasley for Saudi Arabia to lift its blockade and allow fuel into the country.