There are many children among the more than 100 injured people, worldwide media are reporting.
Official Niko Papaefstathiou told state television the two victims were taken to an Athens hospital early Tuesday. Fast paced wildfires swept through the town of Mati, trapping people in cars and on the edge of cliffs as others were forced to jump off to survive.
Help is also needed in Sweden where at least one person has been killed and dozens injured by forest fires there as soaring temperatures continue across much of Europe. "People can not tolerate so much smoke for so many hours", said Achilleas Tzouvaras, a senior fire chief, appalling to people to leave the area after some tried to stay put in their properties.
Greek authorities are looking for dozens of people missing after the deadly wildfires near Athens. The fires are a "national tragedy" and a "biblical disaster with human losses", Greek Interior Minister Panos Skourletis told Sky News.
The coastguard said 19 people were found at sea and rescued while 696 people were picked up from beaches and the coastline by boat.
Greece endures wildfires every summer but the fires that broke out Monday were the deadliest to hit the country in decades.
Tsipras declared three days of national mourning.
Greece Wildfires: Search for Missing Continues as 77 People Killed
Hundreds of people were trapped in the eastern resort of Mati on Monday night as flames whipped around them.
The area around Mati was apparently thickly laden with pine, which would have quickly caught fire. "The wind was indescribable, it was incredible. I've never seen anything like this before in my life". "We ran and headed toward the sea", he added. "We got stuck in traffic and the flames were on top of us". He made it out, he said, and waded in the water until the fires were extinguished.
More than 100 people have been injured in the fires raging on either side of Athens, charring farms and forests, and sending people racing to beaches to be evacuated by navy vessels, yachts and fishing boats. "But as we went further, there was a lot of wind and a lot of current and it started taking us away from the coast".
"We couldn't see any fire".
The operation continued through the night. Israel, Turkey and Bulgaria have also offered assistance. "We are dealing with something completely asymmetrical", Tsipras said. Scenes of devastation and death were reported throughout the region.
According to authorities, 26 of the casualties were found dead in the yard of a villa in Mati, 40 kilometres northeast of Athens, a mix of adults and children huddled together - "perhaps families, friends or strangers, entwined in a last attempt to protect themselves as they tried to reach the sea", said rescuer Vassilis Andriopoulos.
On top of 81 recorded deaths, nearly 190 people were injured from the blaze around the Attica region including 23 children, according to the Civil Protection Agency.
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The show of solidarity was welcomed by many members of the public. President Donald Trump: "Thank you very much". On Thursday, Fox News is on pool duty.