SANAA (Reuters) - Warring factions in the war in Yemen exchanged accusations on Friday of violating a 72-hour ceasefire that began just before midnight on Wednesday, with the Saudi-led coalition saying Houthi forces have breached the truce by attacking several cities in both countries.

The United Nations announced the ceasefire between the parties earlier in the week. It has the possibility for extension if it holds.

The Saudi-led coalition said in a statement on state news agency SPA that Iran-allied Houthi forces have used rockets, shells, and snipers to attack border cities inside Saudi Arabia in the Jizan and Nijran provinces.

It also accused the Houthis of launching attacks on the Yemeni capital, Sanaa, and other provinces such as Taiz, Hajja, Shabwa, Mareb and Aden.

The coalition said it had responded to the Houthi attacks "according to the engagement rules and continuing to exercise the highest self restraints towards the violations of the ceasefire."

The Houthi movement said the coalition struck a number of areas in the border district of Shad, causing damage to properties, according to the Houthi-allied Al-Maseera TV. It added that the Houthis responded to the attacks.

No casualties have been reported by either side.

Several previous ceasefires have failed to pave the way for an end to the conflict, although they have significantly slowed fighting in the war, which has killed at least 10,000 people.

Aid agencies hope to use the truce to reach parts of the country that have been cut off by months of fighting and are in dire humanitarian need.

(Reporting by Mohammed Ghobari in Sanaa and Ahmed Tolba in Cairo; Editing by Dan Grebler)