Nicola Sturgeon accused the Conservatives of being 'charlatans' amid the reports.
Brussels slams UK for 'wasting valuable time' but British side accuses EU of being 'unnecessarily difficult'.
Boris Johnson has been adamant he will not allow the discussions to drag on into the autumn.
Committee believes UK Environent Bill as it stands would only allow Scottish ministers limited say.
The Prime Minister has insisted the two sides are 'not that far apart' as Brexit talks are set to intensify.
Brussels' chief negotiator Michel Barnier said an extension is available if the UK wants it.
The UK's chief negotiator David Frost says both sides remain deadlocked on issues like fishing rights.
The UK Government should seek to extend the transition period to focus on tackling Covid-19, the SNP said.
Speaking to a Holyrood committee, he said tunnelling would be cheaper than the bridge suggested by Boris Johnson.
MEPs ratified the withdrawal agreement as they said goodbye to British colleagues.