Jeremy Corbyn has insisted he will not do a deal with the SNP to gain power at Westminster.
Nicola Sturgeon has said she would try to form an alliance to pursue "progressive policies" if the General Election results in a hung parliament.
The Labour leader, who has already ruled out any agreement with the SNP, spoke out on the issue again on Monday with less than two weeks to go to the General Election.
Mr Corbyn said: "There will be no deals. There will be no alliance. We're fighting this election to win.
"Only Labour or the Tories can win this election and voting Labour is the only way to remove Theresa May from office and build a Scotland for the many not the few."
His comments follow an interview with the BBC, in which Ms Sturgeon said Mr Corbyn was not "credible as an alternative prime minister".
But the SNP leader also said that ''if there was to be a hung Parliament of course we would look to be part of a progressive alliance that pursued progressive policies''.
The SNP won 56 of the 59 seats in Scotland in the 2015 general election, and in the run up to that ballot Tories across the UK sought to raise fears about the impact a possible coalition between Labour and the SNP could have.
Recent opinion polls across the UK have showed Theresa May's lead over Labour shrinking.
An ORB poll for the Sunday Telegraph put support for Labour on 38%, six points behind the Conservatives and a result which would see Jeremy Corbyn outpoll both Ed Miliband and Gordon Brown.
Mr Corbyn was also asked on Monday about how he would deal with Ms Sturgeon if he became prime minister.
Ms Sturgeon's demands for a second independence referendum in the wake of Brexit have been blocked by the UK Government.
The Conservatives say another ballot cannot take place until after Brexit and only if there is public consent for a vote.
Labour's manifesto says the party opposes a second referendum.
Asked during an interview with Bauer and Global radio stations: "Theresa May says now is not the time for another independence referendum.
"You walk into Downing Street in a couple of weeks time what do you say to Nicola Sturgeon?"
Mr Corbyn said: "I'll obviously open discussions with the Government in Scotland and listen very carefully to what the Scottish Parliament says.
"I would ask them to think very carefully about it and suggest it would be much better to have this question dealt with at the conclusion of what are very serious and very important Brexit negotiations, where I am utterly determined to achieve tariff free trade access to the European markets to protect manufacturing and service jobs all across the UK, all across Scotland, Wales and England as well of course."