TANTA, Egypt — Suicide bombers attacked two Coptic churches in Egypt on Palm Sunday, killing at least 44 worshipers and police officers stationed outside, in the deadliest day of violence against Christians in the country in decades.
The Islamic State claimed responsibility for both attacks in a statement via its Aamaq news agency, having recently signaled its intention to escalate a campaign of violence against Egyptian Christians.
The first explosion occurred about 9:30 at St. George’s Church in the Nile Delta city of Tanta, 50 miles north of Cairo, during a Mass. Security officials and a witness said a suicide bomber had barged past security measures and detonated his explosives in the front pews, near the altar.
At least 27 people were killed and 78 injured, officials said.
Hours later, a second explosion occurred at the gates of St. Mark’s Cathedral in the coastal city of Alexandria. That blast killed 17 people and wounded 48 others, the Health Ministry said.
The patriarch of the Egyptian Coptic Church, Pope Tawadros II, who is to meet with Pope Francis on his visit to Egypt on April 28 and 29, was in the church at the time but was not injured, the Interior Ministry said.
Kamil Sadiq Sawiras, a Coptic church official in Alexandria, said a police officer at the church gates had intercepted a suicide bomber, who blew himself up before he could reach the church.
Two police officers and a neighborhood police chief, Adel El-Rakiby, were among the dead.
President Abdel-Fattah el-Sissi called for a state of emergency for three months after the twin bombings, the Associated Press reported.
Sissi accused countries he didn’t name of fueling instability in Egypt, saying that ‘‘Egyptians have foiled plots and efforts by countries and fascist, terrorist organizations that tried to control Egypt.’’
The president did not discuss the process for declaring the state of emergency but according to the Egyptian constitution, the Parliament must approve the action.
The bombings, at the start of the Holy Week leading to Easter, renewed questions about the ability of Sissi to protect minority Christians, who make up about 10 percent of Egypt’s 90 million people.
As forensic teams combed through the bloodstained wreckage of the church in Tanta, witnesses told of how a suicide bomber managed to slip through a side door where security officials had been checking congregants with a metal detector as they entered.
Several deacons, lay Christians who help with the service, were among the dead. Remon Emaad said the church had been on alert since authorities discovered an explosive device nearby last week and defused it.
Soia Williams said her uncle, Methat Moussa, a retired army officer, had been late to Sunday’s service and had gone to the front pews, where the explosion went off.
“We can’t find his body, just a bloodied identity card,” she said.
Egyptian security officials found and defused several other explosive devices at other locations, including at a prominent Sufi Muslim shrine. One bomb had been planted at the Collège Saint Marc, an all-boys school in downtown Alexandria.
Two others were found at the Sidi Abdel Rahim Mosque in Tanta, home to one of the most famous Sufi shrines in the city. Authorities also found two suspected bombs at a local market in the coastal city of Marsa Matruh, state media reported.
The violence on Sunday comes weeks before the visit to Egypt by Francis, in what has been billed as the latest stage of his long-running effort to forge stronger ties with Muslim leaders.
But the pontiff will find himself arriving in a country where the government is struggling to protect Christians and where the Islamic State is intent on driving a wedge between the two religions.
Responding to Sunday’s attacks, Francis offered his condolences to the Copts and to all Egyptians, and referred to the Coptic patriarch as his “brother.”
During his coming trip to Egypt, the Arab world’s most populous country, the pontiff is to visit with Sissi; the leadership of the Coptic Orthodox Church; and the grand imam of Al-Azhar, a 1,000-year-old mosque and university that is revered by Sunni Muslims.
In December, an Islamic State suicide bomber killed 28 people in an attack on a chapel in the grounds of St. Mark’s Coptic Cathedral in Cairo. In February, hundreds of Christians fled their homes in north Sinai after a campaign of assassination and intimidation.
The Islamic State has an active affiliate in Egypt, which has claimed numerous other attacks, including the downing of a MetroJet flight in 2015, which killed more than 200 passengers flying from an Egyptian resort to Russia.
During a visit to Washington last week, Sissi got a warm welcome from President Trump, who hailed him as a “fantastic guy” and a major ally in the battle against Islamist extremists.
But Sissi has had to contend with growing criticism from the country’s Christians over his failure to protect them from attacks.
On Sunday, Trump said he was ‘‘so sad to hear of the terrorist attack’’ against the ally. He said in a tweet that he has ‘‘great confidence’’ that Sissi ‘‘will handle the situation properly.’’