Michael Casey, Jakarta – A bomb exploded in a crowded marketplace in Indonesia's religiously divided province of Maluku Saturday, injuring 53 people, police said.

The 9am blast ripped through a market packed with shoppers in a Christian neighborhood of Ambon, a provincial capital that is divided between warring Christian and Muslim sides.

The island province 1,600 miles east of Jakarta has been wracked by three years of sectarian fighting that has killed 9,000 people.

A Christian activist, Frans, who like many Indonesians uses only one name, said he was inside his house when he heard the explosion. He said he looked outside to see glass, blood and people lying in the street.

"Suddenly there was boom, boom. The house was shaking," he said. "I saw some people lying on the street, and there was blood everywhere. I saw two of them badly injured and lifted into an ambulance." Police Sgt. Ketut Purwato said 53 people were injured.

No one immediately claimed responsibility for the blast, and no one has been arrested, he said. The explosion is the latest in a series of violent incidents that is testing the strength of a peace deal signed in February between the two communities. The truce had succeeded in stemming much of the fighting, but there have been occasional outbreaks of violence since then.

"The situation was very much improving and mutual trust between Muslims and Christians was building up," said Cornelius Bohm, a Christian pastor in Ambon. "This is a terrible setback." The attack came two days after Jafar Umar Thalib – the leader of the militant Islamic group Laskar Jihad, which has been blamed for fueling much of the fighting – was released from a Jakarta jail.

He faces charges of inciting violence in the province by delivering a speech to thousands of his followers in March 26 calling for war. He also has called for them to reject a February peace deal meant to end the fighting between Muslims and Christians in Maluku.

The attack on the Christian village took place soon after that speech. No one has been arrested in the April attack, and Christian leaders suspect that Muslim hardliners were behind it.

As a result of the April attack, the provincial government has declared an emergency and banned all foreigners – including reporters – from the island.

Last week, government officials said security was improving because some some groups, including Laskar Jihad, were turning in weapons.