Hundreds of Buddhists in Myanmar tried to block a shipment of aid to Muslims in Rakhine state where the United Nations has accused the military of ethnic cleansing, with a witness saying protesters threw petrol bombs before police dispersed them by firing into the air.

The protest was testament to rising communal animosity that threatens to complicate the delivery of vital supplies, and came as US President Donald Trump called for a quick end to the violence that has raised concern about Myanmar’s transition from military rule.

The aid shipment, being organized by the International Committee of the Red Cross (ICRC), was bound for the north of the state where insurgent attacks on Aug 25 sparked a military backlash.

The violence has sent more than 420,000 Rohingya Muslims fleeing to neighboring Bangladesh but many remain in Myanmar, hiding in fear of being caught up in more violence without food and other supplies, aid workers believe.

Several hundred people tried to stop a boat being loaded with about 50 tonnes of aid at a dock in the Rakhine State capital of Sittwe late on Wednesday, a government information office said on Thursday.

Protesters, some carrying sticks and metal bars, threw petrol bombs and about 200 police were forced to disperse them by shooting into the air, a witness said, adding that he saw some injured people. Eight people were detained, the government information office said in a release.

A spokeswoman for the ICRC was not immediately available for comment. Police in Sittwe were also not immediately available for comment.

Tension between majority Buddhists and Rohingya in Rakhine state has simmered for decades but it has exploded in violence several times over the past few years, as old prejudices have surfaced with the end of decades of military rule.

The latest bout of bloodshed began in August when Rohingya insurgents attacked about 30 police posts and an army camp, killing about 12 people.

The government says more than 400 people, most of them insurgents have been killed since then.

Rights monitors and fleeing Rohingya say the army and Rakhine Buddhist vigilantes have mounted a campaign aimed at driving out the Muslim population and torching their villages.

Myanmar rejects the charge, saying its forces are tackling insurgents of the Arakan Rohingya Salvation Army who it has accused of setting the fires and attacking civilians.