Doctors Without Borders (MSF) resumed its work in a hospital in Yemen's second city of Aden on Sunday after a one-month suspension following the kidnapping and killing of a patient.
Yemeni government representatives were expected to join a rebel delegation in Sweden on Wednesday for high-stakes peace talks aimed at ending four years of devastating war.
Yemen's president has raised the bar for dialogue with the Houthi rebels controlling Sanaa, saying they must surrender their weapons before the start of any peace talks.
Yemeni President Abedrabbo Mansour Hadi accused Shia rebels and their allies on Tuesday of dashing hopes for peace after they unveiled a new government in areas under their control.
Iran-backed rebels convened Yemen's parliament on Saturday in defiance of the internationally recognised government, prompting condemnation from President Abedrabbo Mansour Hadi.
An air strike by the Saudi-led coalition fighting opponents of President Abedrabbo Mansour Hadi killed six civilians from the same family by mistake on Wednesday, a provincial official said.
Authorities in Yemen's southern city of Aden imposed a curfew on Monday after violence blamed on suspected jihadists killed at least 22 people, pro-government media and security sources said.