COLOMBO, April 21 (Xinhua) -- The death toll from the multiple blasts which shook Sri Lanka on Sunday has risen to 138, while about 500 people were injured, local media reports quoted hospital sources as saying.

Hospital sources said that nine foreigners were among those killed in the blasts while 13 others have been injured.

Four Chinese nationals were injured in the multiple church and hotel explosions, the Chinese Embassy to Sri Lanka said.

The Chinese Embassy has activated emergency response mechanism immediately after the incident, and embassy officials have visited the injured who were in hospital for treatment. The injured Chinese are now in stable condition.

The Chinese Embassy has reminded Chinese citizens and businesses in Sri Lanka to watch out for safety.

In a special statement, the police urged the public to stay indoors and not gather at the explosion sites which had been sealed off.

Television footage showed ambulances rushing the injured to the Colombo National Hospital, the Batticaloa Hospital in the east and the Negombo Hospital on the outskirts of the capital where the explosions took place.

The government said that an urgent security council meeting was underway, with the participation of Prime Minister Ranil Wickremesinghe.

Both President Maithripala Sirisena and Prime Minister Ranil Wickremesinghe have condemned the attacks and appealed for calm.

According to Police, three churches and three hotels have been targeted in the blasts and security has been beefed up across the country.

Officials at the Bandaranaike International Airport have urged passengers to arrived four hours prior to their flight times, adding that no visitors would be allowed inside the airport.

Meanwhile, massive rescue operations are underway at the explosion sites, the police said.

Several explosions were reported from across Sri Lanka on Sunday as hundreds of worshipers gathered at churches to commemorate Easter Sunday, the police said.

Police Spokesperson SP Ruwan Gunasekara said two explosions were reported from the St. Anthony's Church in Kochchikade, in capital Colombo and another from a church in Katana on the outskirts of the capital on Sunday morning. A third explosion was reported from a church in Batticaloa in the east.

Television footage also showed blasts in some star class hotels in the capital.

There has been no claim of responsibility so far for the multiple blasts.