UNITED NATIONS, June 18 (Xinhua) -- The Security Council on Monday condemned the two "heinous and cowardly" terrorist attacks in the eastern Afghan province of Nangarhar over the weekend that led to dozens of deaths.

The members of the Security Council expressed their deepest sympathy and condolences to the families of the victims and to the Afghan government, and wished a speedy recovery to those injured, said the council in a press statement.

The council members underlined the need to hold perpetrators, organizers, financiers and sponsors of these reprehensible acts of terrorism accountable and bring them to justice, and urged all UN member states to cooperate actively with the Afghan government and all other relevant authorities in this regard.

They reaffirmed that terrorism in all its forms and manifestations constitutes one of the most serious threats to international peace and security and stressed the need for all states to combat by all means threats to international peace and security caused by terrorist acts.

At least 15 people were killed and 45 others wounded on Sunday in an explosion in Jalalabad, the capital of Nangarhar. The bombing targeted a meeting between Afghan officials and Taliban members during a rare cease-fire.

On Saturday, 25 people were killed after a suicide car bombing struck a crowd of Taliban militants, members of Afghan security forces and civilians, who were celebrating the temporary cease-fire for the Eid al-Fitr holiday. Fifty-four people were wounded in the attack on the outskirts of Jalalabad, for which the Islamic State claimed responsibility.