TRIPOLI, May 14 (Xinhua) -- The United Nations Children's Fund (UNICEF) on Wednesday said the escalating violence in and around the Libyan capital Tripoli over the past two days threatens to impact nearly half a million children.

"UNICEF has received reports that children, families, and medical staff were stranded in hospitals for hours, including inside Al Jalaa Children Hospital, as fighting closed in. For several hours, emergency services were unable to access the facility to provide the needed help. Families are reporting extreme distress among their children due to the violence," UNICEF said in a statement.

It urged all parties to uphold their obligations under international humanitarian law and the UN Convention on the Rights of the Child to protect children and the infrastructure they rely on.

"We call for a sustained cessation of hostilities to ensure the safety and well-being of every child," it said.

Heavy clashes broke out late Monday in Tripoli between forces loyal to Prime Minister Abdul-Hamed Dbeibah, including the 444 Brigade, and a powerful militant group affiliated with the Presidency Council the Stability Support Apparatus (SSA), amid reports of the death of Abdul Ghani al-Kikli, known as "Ghaniwa," who was the head of the SSA.

Libya's Tripoli-based Government of National Unity declared a ceasefire on Wednesday following intense overnight clashes between the rival militias that spread into central and residential districts of the capital.

Libya has been mired in political turmoil and insecurity since the 2011 overthrow of longtime leader Muammar Gaddafi. The country remains split between rival administrations: an eastern-based government in Tobruk backed by the House of Representatives, and a western-based government in Tripoli aligned with the UN-recognized Presidency Council. ■