French President Emmanuel Macron's lead in voting intention polls widened on Tuesday but his prime minister said a Macron win in Sunday's presidential runoff vote was not guaranteed, as far-right challenger Marine Le Pen accused him of fearmongering.
Three polls for the second-round runoff put Macron at the highest level since before the first round, with an average score of 55.83%, up more than a point on Friday and up more than three points from an average of five polls just before the first round.
But Prime Minister Jean Castex it was too early to claim victory.
"The game is not done and dusted," Castex said on France Inter radio.
An Ipsos poll saw Macron winning 56.5% of the vote, up half a point from Friday and up 3.5 points from 53 on April 8, two days before the first-round vote in which Macron and Le Pen qualified for the second round.
Polls by Opinionway and Ifop, at 56% and 55% respectively, also showed Macron with his highest share of voting intentions since before the first round vote on April 10.
Finance Minister Bruno Le Maire told Europe 1 radio that Le Pen would "hand France's sovereignty to Vladimir Putin and to Russia" if she was elected.
Le Pen has in the past voiced admiration for the Russian president and says she would pull France out of NATO's integrated military command.
Le Maire said a Le Pen victory would mean the end of French sovereignty, an alliance with Putin, a lack of NATO protection and severed ties with Germany.
In a campaign clip, Le Pen accused Macron and his allies of frightening citizens into voting against her.
"Macron, aware of his sombre prospects of winning a second term, has turned to ... blackmail by fear. Fear is the president's only remaining argument," she said.
Centrist Macron and Le Pen are seeking to attract voters who backed far-left leader Jean Luc Melenchon, after he came third in the first round with about 22% of the vote.
Melenchon's party has not given any voting instructions for the runoff but Melenchon has called his followers not to vote for Le Pen.
Macron - then a fresh new face in national politics - won the 2017 election with 66.1% of the vote, but as the incumbent he is weighed down by the yellow vest protest movement against his economic policies, criticism of his management of the COVID crisis and a personal style seen as too haughty.