Budapest,  Hungarian authorities have issued a second-level heatwave alert, as the first hot spell of the summer hit the central European country.

The alert took effect from Saturday until Tuesday midnight, chief medical officer Cecilia Muller informed.

"High temperatures put a strain even on a healthy body, it can cause different complaints, discomfort and a lack of concentration," the National Meteorological Service (OMSZ) said in a statement.

"Young children, the elderly and those with cardiovascular disease are particularly at risk."

According to OMSZ, the average temperature in most parts of the country will be above 25 degrees Celsius, except for three counties located in the mountainous northeast, reports Xinhua news agency.

The temperature is forecast to warm up to 31-35 degrees Celsius during the day.

In most parts of the country, UV-B radiation is also expected to be very strong.

The Mayor's Office of the Hungarian capital informed that so-called "cooling islands" will be set up in Budapest this summer, providing cool water and shade against extreme heat.