COLOMBO — Sri Lanka said on Monday it was invoking emergency powers in the aftermath of devastating bomb attacks on hotels and churches, blamed on militants with foreign links, in which 290 people were killed and nearly 500 wounded.

The emergency law, which gives police and the military extensive powers to detain and interrogate suspects without court orders, went into effect at midnight on Monday, the president’s office said.

Colombo, the seaside capital of the Indian Ocean island, was jittery on Monday.

Police said 87 bomb detonators were found at the city’s main bus station, while an explosive went off near a church where scores were killed on Sunday when bomb squad officials were trying to defuse it.

Investigators said seven suicide bombers took part in the attacks while a government spokesman said an international network was involved.

Police had received a tip-off of a possible attack on churches by a little-known domestic group some 10 days ago, according to a document.

The intelligence report, dated April 11, said a foreign intelligence agency had warned authorities of possible attacks on churches by the leader of the group, the National Thawheed Jama’ut.

Police said 24 people had been arrested, all of whom were Sri Lankan, but they gave no more details.

Two of the suicide bombers blew themselves up at the luxury Shangri-La Hotel on Colombo’s seafront, said Ariyananda Welianga, a senior official at the government’s forensic division. The others targeted three churches and two other hotels.

A fourth hotel and a house in a suburb of the capital Colombo were also hit, but it was not immediately clear how those attacks were carried out.

President Maithripala Sirisena said in a statement the government would seek foreign assistance to track the overseas links.

Most of the dead and wounded were Sri Lankans although government officials said 32 foreigners were killed, including British, US, Australian, Turkish, Indian, Chinese, Danish, Dutch and Portuguese nationals.

Denmark’s richest man Anders Holch Povlsen and his wife lost three of their four children in the attacks, a spokesman for his fashion firm said. — Reuters