COLOMBO, Sri Lanka — Some Americans were among the dead as the death toll climbed to 290 in a series of blasts that rocked Sri Lanka on Easter Sunday, the State Department said.

• Death toll rises to almost 300; more than 500 hurt in blasts
• At least 7 suspects have been arrested in connection to bombings
• Officials say 9 blasts targeted churches, luxury hotels

"While many details of the attacks are still emerging, we can confirm that several U.S. citizens were among those killed," said Secretary of State Michael Pompeo in a statement, who condemned the attacks, calling them "vile."

A Dutch national and British citizens were also caught in the bombings, which left more than 500 wounded.

The nine blasts targeted churches and luxury hotels in and just outside of Sri Lanka's capital of Colombo.

Muslim and Catholic leaders both condemned the bombings that Sri Lankan authorities called a terrorist attack by religious extremists. However, no further details of who is responsible for the attacks have been released.

Officials say seven suspects have been arrested, and two of the blasts are thought to have been carried out by suicide bombers. 

Meanwhile, authorities imposed a nationwide curfew from 6 p.m. to 6 a.m. 

The spokesman, Brig. Atapattu, says a seventh blast occurred at a guesthouse in Dehiwala, killing at least two people. Atapattu says an eighth blast occurred in Dematagoda on the outskirts of Colombo. 

According to a police spokesman, three police officers were killed during a house raid in Dematagoda, Colombo, CNN reported. 

St. Anthony's Shrine and the three hotels where Sunday's blasts took place are in Colombo, the capital, and are frequented by foreign tourists. A National Hospital spokesman, Dr. Samindi Samarakoon, told The Associated Press that they received 47 dead there, including nine foreigners, and were treating more than 200 wounded.

Local TV showed damage at the Cinnamon Grand, Shangri-La and Kingsbury hotels.

The Shangri-La's second-floor restaurant was gutted in the blast, with the ceiling and windows blown out. Loose wires hung and tables were overturned in the blackened space.

A police magistrate was at the hotel to inspect the bodies recovered from the restaurant. From outside the police cordon, three bodies could be seen covered in white sheets.

Alex Agieleson, who was near the shrine, said buildings shook with the blast, and that a number of injured people were carried away in ambulances.

Other blasts were reported at St. Sebastian's Church in Negombo, a majority Catholic town north of Colombo, and at Zion Church in the eastern town of Batticaloa. St. Sebastian's appealed for help on its Facebook page.

The explosion ripped off the roof and knocked out doors and windows at St. Sebastian's, where people carried the wounded away from blood-stained pews, TV footage showed.

Sri Lankan security officials said they were investigating. Police immediately sealed off the areas.

The magnitude of the bloodshed recalled Sri Lanka's decades-long civil war, when separatist Tamil Tigers and other rebel groups targeted the Central Bank, a shopping mall, a Buddhist temple and hotels popular with tourists.

Sri Lanka has long faced a bitter ethnic divide between the majority Sinhalese and the minority Tamils, fueling the civil war as Tamil militants tried to carve out their own homeland.

But in the years since the war ended in 2009, a religious divide has grown, with the rise of Buddhist nationalist groups that stoke anger against the minority Muslims, saying they are stealing from Buddhist temples or desecrating them, or forcing people to convert to Islam. Muslims also own many of Sri Lanka's small shops, and many Muslims suspect small-town jealousy has led to some attacks.

Sinhalese are overwhelmingly Buddhists, while Tamils are mostly Hindu, Muslim and Christian.

Security expert Dave Benson, who served as regional security officer and chief security officer to the U.S embassy in Colombo in the 90's, told Spectrum News it was difficult for him to see a place where he has lived and worked targeted.

"It's heartbreaking on two levels: Personally, my family and I grew to really love the island and the Sri Lankan people, but violence, they are not immune to violence. Terrorism has been alive and well there for decades although not the type that we saw today. So, to see some very common places we've been to and attended blasted like that was very difficult to see," he shared.

Benson also shared his thoughts why soft targets like hotels and churches were targeted in the coordinated attack.

"It's way too early to determine if it's in retaliation for what happened in other places around the world like in New Zealand. But clearly it's very unusual in Sri Lanka to target houses of worship for this type of terrorist activity, so that's particularly troubling but we're seeing a real spike in vulnerability for houses of worship worldwide," Benson described.

Since the attack, the Sri Lankan government has cut off all social media inside their country.

Benson says he doubts this attack was homegrown and hopes the country reaches out to the FBI to help investigate where the planning for this attack originated from.

Prime Minister Ranil Wickremesinghe convened Sri Lanka's top military officials at an emergency meeting of the National Security Council following the blasts. Wickremesinghe tweeted that "the government is taking immediate steps to contain the situation."

The Archbishop of Colombo, Cardinal Malcolm Ranjith, called on Sri Lanka's government to launch a "very impartial strong inquiry" and to punish those found responsible "mercilessly because only animals can behave like that."

There was an outpouring of condemnation from around the world following the attacks.

Turkish President Recep Tayyip Erdogan called the blasts "an assault on all of humanity," while Russian President Vladimir Putin denounced them as "cruel and cynical."

British Prime Minister Teresa May said on Twitter, "We must stand together to make sure that no one should ever have to (practice) their faith in fear."

Foreign Minster of Iran Javad Zariff tweeted his condolences.

President Donald Trump offered his own words of comfort, but mistakenly stated that 138 million died. He then sent a corrected tweet.

It has been a devastating week for Christians. Just last week, the beloved Notre Dame Cathedral suffered a massive fire that destroyed parts of the 12th-century landmark.

Sri Lankan security forces in 2009 defeated Tamil Tiger rebels who had fought to create an independent homeland for the country's ethnic minority Tamils. The U.N. initially estimated the death toll from 26 years of fighting to be about 100,000 but a U.N. experts' panel later said some 45,000 ethnic Tamils may have been killed in the last months of the fighting alone.

Government troops and the Tamil Tigers were both accused of grave human rights violations, which prompted local and international calls for investigations.

The Associated Press contributed to this story.