Serbian president Aleksandar Vucic has been admitted to a hospital after experiencing heart problems, his office said on Saturday.
The 49-year-old was admitted to a military hospital in Belgrade.
A government official who spoke on condition of anonymity told Reuters: "The president is stable now."
A former ultra-nationalist who turned towards the European Union, Vucic became prime minister in 2014 and was elected president in 2017.
Although the presidential role is ceremonial he retains political control as head of the Serbian Progressive Party, which has been in power since 2012.
“General Secretariat of the President of the Republic of Serbia hereby informs the public that in the late afternoon of the 15th of November President of the Republic of Serbia Aleksandar Vučić was admitted at the Military Medical Academy in Belgrade due to cardiovascular issues,” the presidency said in a short statement.