PUISSEGUIN - At least 43 people were killed when a coach carrying elderly day-trippers collided with a lorry and burst into flames in southwest France on Friday, in the country's worst road accident for three decades.

The coach was carrying a club of pensioners on an excursion when it collided with the lorry near the village of Puisseguin among the vineyards of the St Emilion region, east of Bordeaux. Many of the victims were thought to have died in the fire, according to emergency workers and local authorities.

Images shown on French television showed the coach had been completely burned, leaving only a charred shell. "The driver of the lorry appears to have lost control of his vehicle, leaving him stranded in the middle of the road. The bus driver was unable to avoid the accident," Puisseguin mayor Xavier Sublett told reporters.

Locals saw a plume of smoke from several kilometres away. Many said that part of the road was known to be particularly dangerous. The lorry driver was killed. The rest of the victims were passengers on the coach, officials said. "I am astonished at the force of the crash. It will take a lot of time to recover all the bodies," said a fireman at the scene.

Eight people, including the coach driver, managed to escape the burning wreckage -- four of whom were seriously injured, according to a local official. "The bus driver was lightly injured. He had the presence of mind to open the doors to allow as many passengers as possible to leave the bus," said Sublett.

The crash is the deadliest in France since August 1982, when 53 people including 44 children were killed in a motorway pile-up. "The French government has fully mobilised after this terrible tragedy," President Francois Hollande said from Athens, where he is on an official visit. "We are plunged into sadness due to this drama."

Some 20 fire engines and 60 firefighters were dispatched to the scene on Friday, supported by helicopters. A trauma counselling unit and an information hotline were also set up. Prime Minister Manuel Valls, Interior Minister Bernard Cazeneuve and Transport Minister Alain Vidalies travelled to the site, and the National Assembly, or lower house of parliament, observed a minute's silence.

"It's a terrible shock for France," said Valls. The coach, carrying 49 passengers and a driver, departed early Friday from Petit-Palais-Cornemps, a village of 650 residents near the scene of the accident. Pierre Henri-Brandet, spokesman for the interior ministry, told BFMTV that four people "were extremely severely injured" -- two with burns and two with head injuries.

"It's an incredible tragedy with an extremely heavy toll. It's a catastrophe," he said. "They were retired people, elderly people, who were going on a day out." Henri-Brandet said the accident happened just a few minutes after the bus had set off. "We are very affected because all the people on the bus came from the villages in the area," said Jacque Deval, whose brother-in-law and sister-in-law were among the injured.

"My mother and my father-in-law were on the bus. I have just arrived, I don't have any news for the moment, but I'm very scared that they will be on the list of victims," said Delphine Guerineau. The group had been heading south to the nearby region of Landes to visit a facility specialising in Bayonne ham, a local delicacy. If we talk about refugees crisis, then French President Francois Hollande pledged Friday to help Greece implement tough bailout reforms and tackle a major influx of migrants landing on its shores.

The socialist French president is one of the few European leaders to have unabashedly thrown his support behind young leftist Prime Minister Alexis Tsipras during months of fraught talks with its EU and IMF creditor earlier this year. "France must continue to stand by Greece," Hollande said after signing a strategic partnership with Tsipras offering French economic management expertise, especially to tackle tax evasion. On his first visit to Athens since 2013, Hollande praised Greece's determination to stay the course of economic reform, which had put an end to talk of a 'Grexit' -- a Greek exit from the eurozone.

Now the debate is focused on a possible British exit from the EU -- or Brexit -- that would occupy European leaders in December, he said, saying it was a "serious hypothesis" that could not be ignored. He also promised to support Greece as it grapples with a rising number of refugees landing on its shores.

"Greece is our frontier," Hollande said, pledging 60 French experts to help EU border agency Frontex staff emergency registration centres across the region.

"We must cooperate to protect our borders," he added, saying those who did not meet refugee criteria "should be turned back". Earlier on Friday, the International Organisation for Migration said a record 48,000 migrants and refugees had landed on Greek shores over the past five days. Hollande also addressed the Greek parliament, becoming the third French leader to do so after General Charles de Gaulle in 1963 and Nicolas Sarkozy in 2008.

When he arrived on Thursday, Hollande recalled the "bold decisions" taken by Tsipras, who in July agreed to more public spending cuts in return for a three-year, 86-billion-euro ($96-billion) EU bailout to prevent Greece crashing out of the eurozone.

"We did everything, France and Greece... for Greece to remain in Europe," he said.

Tsipras on Friday acknowledged that Hollande "was among those who persuaded me that I had to accept" the bailout. Later, while visiting Athens University, Hollande said that during July's marathon talks, he had closely watched the leaders of countries that had recently joined the eurozone, thinking "who would be next for missing a target, for having a higher-than-forecast debt?"

The French leader has also pleaded for a renegotiation via an interest deferral of the soaring Greek public debt, which is equal to around 200 percent of the country's entire annual economic output. Greece is undergoing a review by EU-IMF auditors after pushing through parliament another round of unpopular tax measures. After a dispute on home foreclosures arose with the creditors, Tsipras on Friday lashed out at "absurd and extreme neo-liberal interventions" that threatened to undermine the bailout agreement.

"Such interventions threaten social peace... Greece signed a deal that it will honour. It did not sign a pact to surrender its sovereignty and destroy its social cohesion," the Greek leader said. Hollande said he supported a Greek request to the European Union for a credit extension of 330 million euros ($363 million) in 2016 to cope with the influx of migrants following the arrival of more than half a million people since January.

"Centres must be created in Turkey so that people will not get as far as Greece, where we will not be able to receive them," he said. Hollande also pledged to encourage French investment in Greece.