Sheikh Khalifa had been battling illness for several years [File: Stephanie McGehee/Reuters}

United Arab Emirates President Sheikh Khalifa bin Zayed Al Nahyan has died, Emirati state news agency WAM reported.

He was 73.

“The Ministry of Presidential Affairs announced that there will be 40 days of official mourning with flags at half mast and three days closure of ministries and official entities at the federal and local levels and the private sector,” the agency wrote on Twitter on Friday.