United Nations, Jan 24 (IANS): The UN Security Council has welcomed the signing of a cease-fire agreement in South Sudan, calling it the first step toward comprehensive reconciliation and nation-building.

The council members Thursday called on all parties to immediately and fully implement the agreement as the first step in a longer process of ensuring durable peace and rule of law, national reconciliation, and the building of effective state institutions, Xinhua reported citing a press statement issued by the council.

Representatives of President Salva Kiir and former deputy president Riek Machar signed the agreement earlier Thursday on the cessation of hostilities, after three weeks of talks mediated by the Intergovernmental Authority on Development (IGAD) in Ethiopia's capital Addis Ababa.

The cease-fire seeks to ease the political dispute in the world's youngest nation between Kiir and Machar, who was removed from office in July 2013 and later accused of attempting a coup.

Tensions escalated Dec 15 into a full-scale conflict between forces loyal to the two men, making 494,000 people internally displaced and 83,900 others flocking into neighbouring countries, over half of them to Uganda, according to U.N. figures.

The 15-member council applauded the tireless efforts by IGAD to achieve the agreement and commended the African Union for its attempts to find a lasting solution to the ongoing crisis in South Sudan and its underlying causes, the statement said.

The council members voiced their unwavering support for the UN mission in South Sudan and strongly condemned the targeted and indiscriminate killings, widespread sexual and gender-based violence, recruitment and use of children, and arbitrary detention.

The council said that some of the acts may amount to war crimes and crimes against humanity and that those responsible for human rights violations and abuses must be held accountable.