NYAL, South Sudan (Reuters) - At the muddy airstrip in Nyal, an opposition-held town in war-ravaged South Sudan, thousands of people have come to collect the first food supplies to have been dropped there in three months.

Supplies were dropped on Sunday and Monday by the United Nations World Food Programme, which said it expected 30,000 people will have come by the time it has delivered the final drop on Tuesday.

The food was shared out before the people went back home through the marshy surroundings of the Sudd swamp carrying supplies on their heads or in boats.

The UN has been dropping food supplies in Nyal every three months since 2014. The town is unsafe to reach by road, with attacks on humanitarian agencies common.

An annual study on trends of violence against humanitarian groups ranked South Sudan as the world’s most dangerous country for aid workers.

Nyal and the dozens of nearby islands in the swamp have become an adopted home for thousands of people since war began in 2013 following a dispute between President Salva Kiir and his former vice president turned rebel leader Riek Machar.

Tens of thousands of people have been killed, a third of the population have fled their homes and the country’s oil-dependent economy has been wrecked.

Earlier this month, Kiir and Machar signed a ceasefire and power-sharing agreement in Khartoum -- the latest internationally-brokered attempt to end war in a country that gained independence in 2011 after a bitter struggle.

Days after it was signed, the United States, Britain and Norway jointly expressed concern that the arrangements between the feuding sides were not realistic or sustainable.