The UN Security Council met behind closed doors Friday after a Saudi-led coalition attack on a bus carrying children in Yemen, diplomats said. The meeting was requested by Bolivia, the Netherlands, Peru, Poland, and Sweden, which are all non-permanent council members. The Saudi-led coalition earlier announced that it had ordered an investigation into the air strike on Thursday that killed at least 29 children traveling on the bus in Yemen. “We have seen the images of children who died,” Dutch Deputy Ambassador Lise Gregoire-van Haaren told reporters. “What is essential at this moment in time is to have a credible and independent investigation.” It remained unclear whether the council would unite and call for action. Kuwait, also a non-permanent council member, is a member of the coalition fighting Huthi rebels in Yemen. Council statements are agreed by consensus, which means any of the 15 members can block a proposed draft demanding an investigation. The United States, France and Britain — three of the five permanent council members — have supported the Saudi coalition in its military campaign, but have expressed concern over the heavy toll on civilians. UN Secretary-General Antonio Guterres on Thursday called for an independent investigation of the attack that left at least 48 others wounded in the raid on the Huthi rebel stronghold of Saada. Since 2015, Saudi Arabia has been leading a military campaign to restore the internationally recognized government to power and push back the Huthis, who still hold the capital Sanaa. The war has left nearly 10,000 people dead and unleashed what the United Nations describes as the world’s worst humanitarian crisis.