FACTBOX: Saudi Arabia's coalition against Yemen's Houthis

Saudi Ambassador to Washington Adel al-Jubeir said a coalition of more than 10 countries had joined the military campaign to try to protect Hadi's government, without naming the countries involved.

The United Arab Emirates (UAE), Bahrain, Kuwait, and Qatar signed a joint statement with Saudi Arabia announcing the military action, leaving Oman as the only member of the Gulf Cooperation Council (GCC) not to join the coalition.

Egypt, Jordan and Sudan said their forces were involved in the operation, with Sudan pledging ground troops as well as warplanes.

Morocco said on Friday it would make forces already stationed in the UAE available to the coalition, and provide intelligence and logistical support.

Pakistan said on Friday it had not decided whether to heed a request for military support from Saudi Arabia, but reaffirmed its support for the kingdom.

The White House said the United States would give logistical and intelligence support. Turkey also declared its support.

Iran demanded an immediate halt to military action, while China expressed concern and called for dialogue.

The following is a list of countries that have confirmed their participation in the coalition:

-Saudi Arabia leads the coalition. Al-Arabiya reported it had deployed 100 fighter jets, 150,000 soldiers and some naval units.

-The UAE signed the GCC statement. Al-Arabiya reported it had deployed 30 fighter jets.

-Bahrain signed the GCC statement. Al-Arabiya reported it had deployed 15 fighter jets.

-Kuwait signed the GCC statement. Al-Arabiya reported it had deployed 15 fighter jets.

-Qatar signed the GCC statement. Al-Arabiya reported it had deployed 10 fighter jets.

-Jordan said its fighter jets were involved in the operation. Al-Arabiya said six Jordanian jets were involved.

-Sudan said its air and ground forces would take part in the operation. Al-Arabiya said three Sudanese fighter jets were involved.

-Egypt said its naval and air forces were involved in the campaign. Foreign Minister Sameh Shoukry said ground forces could become involved "if necessary".

-Morocco said it would make its forces stationed in the UAE available to the coalition. It has UAE-based fighter jets that have been used in operations against Islamic State but did not confirm media reports this was what it had in mind.

(Reporting by Reem Shamseddine; Writing by Sam Wilkin; Editing by Giles Elgood)