Saudi-led air raids hit the Sanaa headquarters of Yemen's former president Ali Abdullah Saleh's General People's Congress party late on Sunday, killing and wounding several people, witnesses and a party official said.
The strikes coincided with a visit to the capital by the U.N. special envoy to Yemen, Ismail Ould Cheikh Ahmed, who is seeking to arrange a pause in fighting until the end of the Muslim holy month of Ramadan on about July 17 to allow for deliveries of humanitarian aid.
Saleh is an ally of the country's dominant Houthi movement. A Saudi-led coalition has orchestrated a more than three-month bombing campaign against the Houthis and army units loyal to Saleh to try to restore President Abd-Rabbu Mansour Hadi, who is in exile in Riyadh.
The General People's Congress party's assistant secretary general, Faeqa al-Sayed, said the party headquarters had been destroyed.
The raids were an attempt to make the talks with the U.N. fail, she said, adding that several employees and others were killed.
"This will not make us back down on our efforts .... to create the suitable environment to cooperate with the United Nations," she said in a statement on the party's website.
Ould Cheikh Ahmed arrived in Sanaa on Sunday for talks with the Houthis, after discussions in Muscat, Oman to push for a pause in fighting that has killed nearly 3,000 since March.
Both sides largely observed a five-day truce brokered by the United Nations in May to allow in fuel and medicine to civilians trapped in conflict zones.
Saleh, the strongman who resigned following 2011 "Arab Spring" protests after more than three decades in power, has emerged as the main military ally of the Houthi Shi'ite fighters.