The World Food Program said on Sunday it had carried out its first ever successful high-altitude airdrop, to deliver 20 tons of food aid to the besieged Syrian city of Deir Ezzor.

A previous attempt to drop aid to the city where 200,000 people have been living under siege by the Islamic State (ISIS) group since March 2014 failed in February, WFP said in a statement.

The successful airdrop was the first time WFP has managed to get aid to the city, around 120 kilometers (70 miles) southeast of the jihadist movement’s de facto capital Raqa, since the start of the siege over two years ago.

The supplies — enough beans, chickpeas and rice to feed 2,500 people for a month — were collected for distribution in the city by the Syrian Arab Red Crescent.

“More airdrops are planned for the coming days to meet food and other humanitarian needs for the besieged population,” WFP said, adding that airdrops would always be a last resort used when land access was impossible.

ISIS has been battling to capture the airbase in Deir Ezzor, which provides the only supply route other than airdrops to the government-held sector of the city.

The February airdrop failed with some of the pallets missing the drop zone and others being damaged due to their parachutes failing to function properly.

In May of 2015, ISIS cut off the supply line to Deir Ezzor and the city has been besieged since.

In January, ISIS launched an attack on Deir Ezzor, killing at least 85 civilians and 50 regime forces. It then abducted at least 400 civilians, including women and children, in the city. It subsequently released 270 of those kidnapped.

AFP contributed to this report.