♤ The situation in Yemen is, the UN says, the world's worst man-made humanitarian disaster.

♤ More than 9,245 people have been killed and 52,800 injured since March 2015, the UN says.

♤ At least 5,558 of those killed, and 9,065 of those injured up to 14 December 2017 were civilians. Saudi-led coalition air strikes were the leading cause of overall civilian casualties.

♤ According to the UN Human Rights Council, civilians have repeatedly been the victims of "unrelenting violations of international humanitarian law".

♤ What happens in Yemen can greatly exacerbate regional tensions. It also worries the West because of the threat of attacks emanating from the country as it becomes more unstable.

♤ The conflict between the Houthis and the government is also seen as part of a regional power struggle between Shia-ruled Iran and Sunni-ruled Saudi Arabia.

♤ Jihadist militants from al-Qaeda in the Arabian Peninsula (AQAP) and rival affiliates of the Islamic State group (IS) have taken advantage of the chaos by seizing territory in the south and carrying out deadly attacks, notably in Aden.

♤ Yemen is strategically important because it sits on the Bab al-Mandab strait, a narrow waterway linking the Red Sea with the Gulf of Aden, through which much of the world's oil shipments pass.