UN Secretary-General Ban Ki-moon and the UN Security Council on Thursday condemned terrorist attacks on a mosque in Sana'a, the capital of Yemen, during prayers for the Eid al-Adha holiday earlier in the day, which resulted in a large number of deaths and casualties.

The secretary-general, in a statement issued here by his spokesman, expressed "his deepest condolences and sympathies to the families of the victims and to the people of Yemen."

"Such attacks against places of worship, or civilians anywhere, cannot be justified by any cause," said the statement. "The secretary-general calls for a full investigation of the bombing and for the perpetrators to be brought to justice."

Also on Thursday, the 15-nation Security Council condemned "in the strongest terms the horrific terrorist attacks" on the mosque in Sana'a, said a separate statement issued to the press here by the UN body. "The members of the Security Council expressed their deep sympathy and condolences to the families and friends of those killed and injured by these heinous acts, as well as to the people and the government of Yemen."

The Islamic State (IS) claimed responsibility for twin suicide bombing attacks Thursday against a mosque in Yemen's capital of Sanaa, which left 30 people dead. Scores of others were injured when two suicide bombings hit the mosque during Eid al-Adha prayers in Sanaa Thursday morning.

"The members of the Security Council reaffirmed that terrorism in all its forms and manifestations constitutes one of the most serious threats to international peace and security and that any acts of terrorism are criminal and unjustifiable regardless of their motivation, wherever and whenever, and by whomsoever committed," the council statement said.

"The members of the Security Council reiterated their determination to combat all forms of terrorism, in accordance with their responsibilities under the Charter of the United Nations," the statement said, adding that "the Security Council underlined the need to bring perpetrators, organizers, financiers and sponsors of these reprehensible acts of terrorism to justice and urged all States, in accordance with their obligations under international law and relevant Security Council resolutions, to cooperate actively with the Yemeni authorities in this regard."

The members of the Security Council reminded States that they must ensure that measures taken to combat terrorism comply with all their obligations under international law, in particular international human rights, refugee and humanitarian law, the statement added.

Al-Qaida and the IS have intensified their attacks against the Shiite Houthi group since the Houthis started to advance into the southern regions, where the terrorist groups are active. They have conducted a series of suicide attacks in Sana'a since early this year that killed more than 100 people.

Security worsened dramatically in Yemen since March when war erupted in several provinces in the country's southern and northern regions after President Abd-Rabbu Mansour Hadi was forced to take refuge in Saudi Arabia by the Shiite Houthi group.

Saudi-backed government forces have recently launched several military campaigns against Houthi fighters in an attempt to drive them out of the territory under their control.

In the past four days alone, more than 236 civilians have been killed in airstrikes conducted by a Saudi-led coalition against the Houthi rebels, Yemen's Saba news agency reported.

Hundreds of others were wounded and many public and private properties destroyed in the air raids, it said.

The United Nations said more than 4,500 people had been killed in Yemen since March, including around 400 children.