Warplanes from Arab coalition have targeted Houthi rebels across Yemen, just days after a humanitarian ceasefire ended.
Rebel positions in Yemen's capital Sanaa, as well as Aden in the south, and Marib province in the east, were all hit by the strikes on Friday, residents said.
In north Sanaa, coalition warplanes targeted a stadium and a camp of the Republican Guards loyal to ousted president Ali Abdullah Saleh, who has sided with the Houthis.
In all, eight rebel and allied targets were hit in and around Sanaa, including Dalaimi air base near the international airport, witnesses said.
There were no immediate casualty figures available for strikes in Sanaa and in Marib province.
In Aden, at least 16 Houthis and allied fighters were killed in raids and fighting, sources said, adding that three fighters who back President Abd-Rabbu Mansour Hadi also died in clashes.
Hayef al-Bakri, a local pro-government official in the port city, urged the coalition to intervene on the ground in Aden "to save residents".
He told the AFP news agency that civilians in Aden were facing "abuses" at the hands of the rebels.
The coalition has said it is determined to pursue its air campaign against the Houthis in order to restore the authority of Hadi, who has fled to Riyadh with members of his government.
The UN will host a conference on Yemen next week in Geneva, despite uncertainty over who will attend.