Warring parties in Yemen exchanged heavy weapons fire overnight in Hodeidah, according to residents and military sources. The clashes came as the United Nations scrambled to salvage a ceasefire deal in the Yemeni port city that is a lifeline for millions at risk of starvation. Witnesses say the clashes were the heaviest since the ceasefire went into effect on December 18. Houthi forces and troops backed by a Saudi-led coalition traded artillery, mortar and rocket salvoes late on Sunday and early on Monday, with explosions heard across the Red Sea city, Reuters reports. The Houthis “tried a surprise assault on our troops but we stopped them,” a source from the internationally-recognized government said. However, the Houthis’ Al Masirah TV accused government forces of shelling their positions without provocation.