The U.N. on Tuesday condemned airstrikes by the Saudi-Emirati coalition against a Houthi target in Sana’a, Yemen, that killed some 20 people overnight Monday, including civilians. The airstrikes came hours after Houthi fighters claimed responsibility for an attack on the United Arab Emirates which killed three people. The Saudi-led coalition said it launched additional air raids on Sana’a Tuesday. Analysts warn the recent attacks could represent a dangerous escalation in the ongoing war in Yemen, which has triggered what the U.N. has called the world’s worst humanitarian crisis.