A group of international donors pledged $6.4 billion (4.0 billion pounds) of aid to Yemen, to help the impoverished country rebuild after it was hit by political unrest and an insurgency waged by Al Qaeda, a senior World Bank official said on Tuesday.

"The total number is $6.396 billion, to fund the short term and portions of the long term," Inger Andersen, vice president for the Middle East and North Africa at the World Bank, said at a donors' meeting in Riyadh.

The figure includes $3.25 billion in aid already pledged earlier by Saudi Arabia, of which a $1 billion loan has been paid to Yemen's central bank. The United States and Britain are among other donors.

(Reporting by Angus McDowall; Writing by Andrew Torchia)