Israel is signaling a wider campaign against Houthi militants in Yemen, a mountainous and impoverished country more than 1,000 miles from Israeli territory.

Israel has severely weakened Hamas and Hezbollah. Now it's going after another member of Iran's so-called axis of resistance: the Houthi rebels of Yemen.

The head of the World Health Organization said he was about to board a flight in the Yemeni capital when the airport came under bombardment.