Scottish Conservative leader Douglas Ross said “nothing is off the table” when it comes to his offer to work with pro-unionist parties in Scotland despite their refusal to do so.
The Moray MP and party leader wrote a letter on Saturday seeking an “open discussion” about cooperation between the Scottish Conservatives and Scottish Labour to fight the “threat of independence”.
The move came in response to the formation of Alex Salmond’s new Alba Party, which has already added two SNP MPs to its ranks.
However, Mr Sarwar ruled out working with the Tories, describing the move as Mr Ross’ “latest desperate plea for attention”.
Mr Rennie also refused the request to join forces with the other pro-unionist parties.
Speaking during a press conference with journalists on Sunday, Mr Ross said the nationalists represent a “major threat”.
When asked if he would be willing to stand down a Scottish Conservative candidate in constituencies where opposition parties are in a better position to challenge the SNP, Mr Ross said he is “willing to look at every and all options on the table”.
He added: “At the moment, given the threat we are facing, nothing is off the table.”
Mr Ross described it as “naive in the extreme of Anas (Sarwar) to suggest that we can somehow ignore the threat that is being posed by the SNP and the Alba Party”.
He added: “If Scottish Labour and the Scottish Liberal Democrats can’t wake up to that threat then they are not recognising the clear and present danger that there is from the nationalists.
“They are gaming the system. Alex Salmond understands they could have a super-majority of nationalist supporting MSPs if this works out and clearly that would be to the detriment of the unionist parties which is why I think we’ve got to work together in the face of this threat.”
The Scottish Conservative leader, who is seeking election in the Highlands and Islands region, said “clearly there is splits and divisons within the SNP”.
He added: “That is not new as we’ve seen over the last few months and indeed years.
“Whether it’s on internal party policy, whether it’s on personalities, the SNP is split.
“But the nationalists put that to one side to push ahead with their only priority which is an independence refernedum and that is why the threat is real.
“They’re willing to put aside personal differences, political differences to achieve their number one aim which is to separate the country.
“That is why those of us on the pro-UK side have to do the same.”
An SNP spokesman said: “The SNP is focused on tackling Covid-19 and securing a strong, fair and green recovery for Scotland as an independent country in a post-pandemic referendum.
“Only both votes SNP on May 6 can put Scotland’s future in Scotland’s hands – not Boris Johnson’s.”