Here are the latest developments on Europe's heatwave.
Scientists have shown that recurring heatwaves are a clear marker of global warming, and warn they are set to become more frequent, longer and more intense.
"The transport network comes under severe strain in periods of extreme heat. You probably know this already, but railways cannot withstand temperatures above 50 degrees," the head of the Ile-de-France greater Paris region, Valerie Pecresse, told journalists.
"That is why we have advised all passengers who can to postpone their journeys, particularly vulnerable people, and for everyone who is able to work from home to do so."
The UK's meteorological office issued the highest level of heat warning for parts of central and southern England for Wednesday and Thursday, with temperatures in the shade potentially rising as high as 40C in some places.
"An exceptional spell of hot and humid weather is expected across this region" covering London, Birmingham, Bath and other areas of England, the Met Office said in Monday's statement, a month after the UK broke its May temperature record.
"It is now likely the current highest temperature on record for June will be broken, this being 35.6C recorded in Southampton in June 1976 and Camden Square in June 1957," the forecaster said.
Thirteen people drowned across France at the weekend, the civil defence said, as the country braced for a peak of 43C in the southwest with half the country on red alert for unhealthy heat.
The authorities urged people not to swim unsupervised, as forecasters warned the extreme weather episode could end up being as serious as a 2003 heatwave that claimed the lives of nearly 15,000 people nationwide.
Some 845 schools were shut on Monday because of the heat, with another 1,800 set to allow students to leave earlier than usual.
Spain entered on Monday the second day of a heatwave which dragged the usually cooler Basque country on the border with France towards temperatures potentially exceeding 40C, prompting a red weather warning and the authorities urging people to keep their windows closed.
The heat had already forced the authorities to cancel a planned screening in Madrid of Spain's World Cup clash against Saudi Arabia, which the European champions won 4-0.
Spain's weather service Aemet warned of "extremely high" temperatures for the season, day and night, until Wednesday, with temperatures forecast to hit 44C in some areas.
Areas in central and northern Portugal faced potential temperatures "close to previously recorded highs", while temperatures would be above average but "relatively typical" elsewhere, the IPMA weather agency said.
Three northern inland districts were placed on orange alert until Tuesday, said Meteo Portugal, which warned that the winds would worsen the "thermal discomfort".
Temperatures in Belgium are expected to be "the hottest ever recorded" in the coming week, warned David Dehenauw, head of forecasting at the IRM meteorological institute.
The French and Belgian authorities also cancelled or cut back rail services because of fears of breakdowns causing logjams and delays.
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