BELGRADE, Serbia >> Authorities in western Balkan countries warned citizens Friday to be cautious, drink water and avoid sunshine during an early heat wave that sent temperatures soaring to up to 104 degrees.

“Don’t stay in the sun between 11 a.m. and 5 p.m.,” warned Serbia’s Public Health Institute in its instructions to citizens. “If you must go out, please take a bottle of water along.”

Meteorologists say the heat in the region this week came from Africa, carrying sand particles that created a cloudlike layer that dimmed the skyline.

The sweltering heat was the worst in big cities, where concrete sizzled even in the evening, and where nights offered only moderate respite as temperatures remained above 68 degrees.

While hot summers are normal in the Balkans, temperatures don’t typically climb so high in mid-June that they promp weather alerts and warnings.

— The Associated Press