The president of Yemen has resigned - along with his prime minister - in protest at the takeover of the capital Sana'a by Shia Houthi rebels, creating a dangerous political vacuum.
President Abdrabbuh Mansour Hadi said he could not continue after the Houthis failed to honour a peace deal, the BBC reported.
Parliament has reportedly refused to accept the resignations.
Security sources have told the BBC that Yemen's intelligence chief, Ali Hassan al-Ahmedi, has also stepped down.
There are reports of explosions in the southern port city of Aden, where President Hadi has a strong following.
Houthi rebel figures publicly welcomed the resignation of the president with one proposing the creation of a ruling council.
Houthi leaders had previously committed themselves to withdrawing from key positions around the presidential palace and the home of President Hadi.
The US, which is helping fight al-Qaeda militants in Yemen, said it was still assessing the implications of President Hadi's move.