Photo: Yemeni Houthi rebels check the Balili mosque in the capital Sanaa, following an explosion on September 24, 2015 on the first day of Eid al-Adha, the Feast of the Sacrifice.(Photo: MOHAMMED HUWAIS, AFP/Getty Images)

At least 25 people were killed in a suicide bombing at a mosque in Yemen's capital Thursday as worshipers said prayers to mark the Muslim holy day of Eid al-Adha.

Two explosions struck the al-Bolayli mosque in Sanaa on the holiday, also known as the Feast of Sacrifice, one of Islam's two most important. Dozens of others were wounded in the morning blast.

An Islamic State affiliate in Yemen claimed responsibility for the attack, which took place in an area controlled by Shiite rebels known as the Houthis. The Islamic State is a Sunni militant group, and it has targeted the Shiite rebels in the past because it views them as heretics.

Officials said the bomber put an explosive device in his shoe, which caused the initial explosion and as worshipers ran to the door, he blew himself up in the middle of the crowd, the Associated Press reported.

U.N. Secretary-General Ban Ki-moon condemned the attack and called for the perpetrators to be brought to justice.

“Such attacks against places of worship, or civilians anywhere, cannot be justified by any cause,” he said in a statement issued by his spokesperson in New York.

The attack came two days after Yemen's President Abed Rabbo Mansour Hadi returned to the southern port city of Aden from Saudi Arabia, where he was in exile after fleeing his country in March. The Houthis, who are being targeted in airstrikes by a Saudi-led coalition, remain in control of large sections of the country.

Thousands of people, including more than 2,200 civilians, have been killed in the fighting since late March, according to the United Nations.

In March, more than 130 were killed in suicide bombings at two Shiite mosques in Sanaa in one of the deadliest attacks in the war-torn nation's history. The Islamic State affiliate in the country also took responsibility for that event.