Saudi-led warplanes bombed the Sanaa headquarters of the Yemeni party headed by rebel-allied former president Ali Abdullah Saleh overnight, the party said as officials reported 46 killed in other strikes.
The attack on the offices of the General People's Congress caused "some deaths" among employees and guards of the building in the south of the capital, party official Faeqa al-Sayed said.
It came as some GPC members were meeting the UN's Yemen envoy Ismail Ould Cheikh Ahmed in another part of the city.
Sayed called the attack "an attempt to derail the UN envoy's mission".
Cheikh Ahmed arrived in Yemen on Sunday and called for a humanitarian ceasefire after months of conflict in the impoverished Arabian Peninsula nation.
"As we were conducting consultations with the UN envoy to find solutions to the political crisis gripping the country... Saudi forces bombed the party headquarters, killing employees and guards and destroying the building," Sayed was quoted as saying by the GPC's news site, Almotamar.net.
Farther south in Lahj province, coalition warplanes struck a market in an attack that a provincial official said was "accidental" and killed 41 people, believed to be mostly civilians.
Signup to our newsletter and follow us on Facebook and Twitter!
Another 34 people were wounded in the strike, the official said, adding that rebels sometimes station military convoys in the market.
AFP could not confirm if the casualties were all civilians, and there was no immediate explanation from the coalition leadership in Saudi Arabia.
Another air strike targeting a rebel-held government building in adjacent Aden also hit a nearby home and killed five residents, a provincial official there said.
Also in Aden, rebels fired "12 rockets" at a port near the oil refinery, sparking new fires, just two days after flames were put out there following days of similar attacks on the area, said Aden Refinery Co. spokesman Naser al-Shayef.
The Saudi-led coalition began a campaign of air strikes against the Huthis and their allies in March after the insurgents seized Sanaa and then advanced south, forcing the government to flee to Riyadh.
More than 21.1 million people -- over 80 percent of Yemen's population -- need aid, with 13 million facing food shortages.
Upwards of 2,800 people have been killed in Yemen since March, according to UN figures.
Saleh, who ruled for 33 years before being forced from power in 2012 after a bloody year-long uprising, threw the support of his loyalists in the army behind the Huthis.