Southeastern Europe baked in searing temperatures Friday, with nearly 30 deaths blamed on the heat in recent days across the region.

Electricity supplies, particularly in Greece and Albania, were straining to keep up with demand as air conditioning use spiked during the year's first major heat wave.

Temperatures reached 40 (104F) degrees Celsius in Athens on Friday, with a top recorded temperature of 45 C (113F) on the island of Rhodes, according to state NET television.

The heat in Athens, exacerbated by high humidity and pollution levels, had tourists and residents scurrying for shade and guzzling cold water. Many abandoned the city for local beaches.

Meteorologists said this could be the warmest June in 90 years and that Greece was on track for the hottest summer in a quarter century - adding fuel to global-warming fears.

Romania has been particularly hard hit. Nineteen people have died of heat-related causes in the past few days, including 14 in the capital, Bucharest, the country's Health Ministry said.

One man drowned in the southern city of Calarasi while trying to cool off in a river.

Romania's Centre for Emergency Situations warned that temperatures in the south are expected to climb to 38 C (100F) over the next two days. Storms and torrential rain were also expected on the weekend, the centre said.

Dozens of villages in western Romania were without electricity following heavy storms overnight.

In Serbia, doctors said at least seven people had died in recent days of heat-related causes, and authorities warned the public to avoid going outdoors. In neighbouring Macedonia, temperatures were also pushing 40 C (104F) Friday and officials said they had fielded numerous emergency calls from elderly people suffering cardiac and asthma problems.

To the south in Albania, at least three people died as a result of the heat, including a 43-year-old mother of four who collapsed while tending her fields.

Hundreds of children in Kucove, 110 kilometres south of the capital, Tirana, were taken to health care units, while the Health Ministry ordered air conditioned emergency rooms to be set up around the country.

Parts of Tirana have also suffered nine-hour power cuts this week, as hydroelectric reservoir levels remain low after a dry winter.

Evangelos Lekatsas, who oversees Greece's electrical grid, said Greece had increased electricity exports to Albania to help it cope.

But Greece itself faced power problems, with many parts of the country suffering blackouts for the fourth day running. The state power company appealed to the public to limit its electricity use.

Many parts of the country are expected to reach 43C (109F) this weekend, some of the highest temperatures since the record-breaking summer of 1987, when hundreds of people died due to the heat.