File photo of Sudanese policeman in the eastern state of Kasala, 15 August 2016 (AFP)
A man attacked worshippers with a knife inside a mosque in Sudan's eastern state of Kasala on Tuesday, killing three people and wounding several others, a police officer told AFP.
Kasala police chief Yahi Sulayman said it took place when worshippers had gathered for evening prayers in a mosque in Kasala city, which borders Eritrea.
"Three people have been killed and several wounded," Sulayman said.
Residents said the attacker had tried to address worshippers who refused to listen to him and then started stabbing them.
"People in the mosque then retaliated and killed the attacker," Sulayman said, adding that the identity of the attacker had not been established.
Since January, Sudan has shut its eastern border with Eritrea, days after Khartoum declared an emergency in the state of Kasala.
Officials say the decision was part of a government campaign to collect illegal arms in the state.
Hundreds of Sudanese soldiers have been deployed in Kasala in recent months, residents say.
Thousands of Eritreans, fleeing a repressive government at home, cross into Sudan illegally through the border with Kasala every year and later make perilous voyages across the Mediterranean to Europe.
Apart from Kasala, a state of emergency is in place in Sudan's war-torn regions of Darfur, Blue Nile, South Kordofan and North Kordofan.