The UN and the US are working fervently behind the scenes to ensure attendance by all sides - but conditions have been set.
Analysis: One of the most radical transformations in the history of US intelligence is reportedly underway, shifting its agents from traditional spying ops to snooping roles.
A tripartite deal has been reached to impose international sanctions against former Yemeni president Ali Abdullah Saleh and Houthi leaders.
US documents sent to the UN sanctions committee on Yemen accuse the former president of aiding the Houthis in their takeover of Sanaa.
