A powerful heatwave continues to grip large parts of Europe, prompting authorities in several countries to issue warnings, close schools and advise residents and tourists to limit travel. France has expanded its highest-level heat warning to cover millions of residents, the UK has issued a rare top-tier alert with temperatures forecast to reach 40C, while Italy, Belgium, Germany and Spain are also seeing disruptions linked to the extreme weather.FranceFrance recorded its highest average temperature for the month of June, with daytime and nighttime temperatures averaging 29.2C, according to provisional data from Meteo France.Authorities expanded the highest-level red heatwave alert to 54 of the country's 96 mainland departments, affecting an estimated 39 million people. More than 1,350 schools were closed due to the extreme heat.Prime Minister Sebastien Lecornu was due to chair a fresh crisis meeting on Tuesday to assess the situation, AFP reported.The heatwave has also been linked to safety concerns. Sports and Youth Minister Marina Ferrari said around 20 people had drowned since the start of the weekend as residents sought relief in rivers, lakes and coastal waters.In south-eastern France, two children aged two and four were found dead in their family's car on Monday as temperatures soared.Regional authorities in Paris advised vulnerable travellers to postpone journeys, warning that rail infrastructure comes under severe strain during periods of extreme heat.United KingdomThe UK Met Office issued its highest-level heat warning for parts of central and southern England for Wednesday and Thursday.Temperatures could reach as high as 40C in some areas, including London, Birmingham and Bath.The Met Office described the conditions as "an exceptional spell of hot and humid weather" and said the country's June temperature record of 35.6C, set in 1976 and matched in 1957, is likely to be broken.GermanyGermany reported five fatal swimming accidents over the weekend amid the hot weather.Authorities said two men aged 20 and 22 drowned in lakes in Bavaria, while a 79-year-old woman died in the Baltic Sea. Other fatalities were reported in Brandenburg and North Rhine-Westphalia.The heatwave also caused disruptions at Frankfurt Airport, where emergency services treated several passengers after an aircraft remained on the tarmac for more than an hour before departure.BelgiumBelgium's heatwave is expected to last about a week and could become the hottest ever recorded in the country, according to David Dehenauw, head of forecasting at the IRM meteorological institute, as reported by AFP.Some schools have reduced classes to half-day schedules as temperatures continue to rise.ItalyItaly's Health Ministry issued red heatwave alerts for 15 cities, including Rome and Milan, on Tuesday. The number of cities under the highest-level warning is expected to rise to 16 on Wednesday. Under a red alert, authorities advise residents to avoid outdoor activities during the hottest hours of the day, stay hydrated, eat light meals and use cooling measures to reduce heat exposure. The heatwave has also affected public transport in Rome. The city's transport authority, Atac, said batteries on newly introduced electric buses are being depleted more quickly because air-conditioning systems are running continuously in the extreme temperatures. "We are organising the service to face up to this unusual heatwave," Atac was quoted as saying by Italian daily Corriere della Sera.Spain Spain continues to experience extreme temperatures, with Madrid recording highs of 40C on Monday. In response, city authorities opened a "climate refuge" centre for homeless and vulnerable residents. The facility operates between midday and 8 pm and provides water, food and hygiene services to help people cope with the heat. The hot weather has also affected southern Spain. In Cordoba, residents sought relief from soaring temperatures as the heatwave persisted across large parts of the country.Portugal Portugal's weather agency said Tuesday is expected to mark the peak of the current heatwave in the country.What travellers should expectTourists travelling across Europe this week may encounter transport delays, service disruptions and restrictions on outdoor activities in some regions.Scientists have repeatedly identified recurring heatwaves as a key indicator of climate change, warning that such events are becoming more frequent, lasting longer and reaching higher temperatures across Europe.(With inputs from agencies)