SINGAPORE - President Tony Tan Keng Yam and Prime Minister Lee Hsien Loong have written to Egypt's leaders to offer their condolences over the weekend bombings of two Coptic Christian churches that killed 44 people, the Ministry of Foreign Affairs (MFA) said in a statement.

More than 100 people were injured in the attacks on Sunday on the St. Mark's Cathedral in the Mediterranean city of Alexandria and the Mar Girgis Church in the Nile delta city of Tanta.

The Islamic State in Iraq and Syria (ISIS) militant group claimed responsibility for the attacks.

In a letter to Egyptian President Abdel Fattah Al Sisi, President Tan said he was appalled by the attacks.

"On behalf of the people of Singapore, I express my heartfelt condolences to Your Excellency and the families of the victims, and wish those injured a speedy recovery," he wrote.

"Singapore strongly condemns the heinous attacks. We stand in solidarity with Egypt and her people in the fight against the scourge of terrorism," he added.

"I am confident that under your leadership, the Egyptian people will remain united against all attempts to sow hatred and division. Our thoughts and prayers are with Egypt and its people during this difficult time."

Writing to Egypt's Prime Minister Sherif Ismail, PM Lee said he was shocked by the deadly bomb attacks.

"Singapore strongly condemns such reprehensible acts against civilians at places of worship aimed to sow division and foment hatred," he wrote.

"Egypt has long stood firm and united against terror and violence. I am confident that Egypt and her people will overcome the latest attacks, and that Egyptian society will remain strong and cohesive," he added.