GENEVA (Reuters) - Peace talks between Yemen’s warring parties will start by trying to build trust between the two sides, who are both keen to agree prisoner releases, and substance will come later, U.N. Special Envoy Martin Griffiths told reporters on Wednesday.

Griffiths, who plans a three-day first round in Geneva and hopes to reactivate formal peace negotiations, said he was not fazed by the delayed arrival of the Houthi delegation, adding that Houthi leader Abdulmalik al Houthi was impatient for rapid progress in the talks.