At least 12 fighters died on Friday in clashes between loyalists and rebels in Yemen's Marib province east of Sanaa, two days ahead of a UN-announced ceasefire, military sources said.
They said the clashes, which according to a preliminary toll killed seven pro-government fighters and five rebels, broke out around the town of Sarwah which loyalists have been trying for months to recapture from Shiite Huthi rebels.
Saudi-led Arab coalition warplanes circled overhead but did not drop any bombs or fire missiles, an AFP correspondent at the scene said.
The rebels said on their website, sabanews.net, that a three-pronged government offensive was repelled with the loss of 35 loyalists.
A ceasefire is due to come into effect in Yemen at midnight on Sunday, with the UN hoping it can be the cornerstone of a peace deal at talks due to start on April 18 in Kuwait.
The UN says the Yemen conflict has cost the lives of about 6,300 people – nearly half of them civilians – since the Arab coalition intervened on the side of the government in March 2015.