The Scottish government has been accused of double standards over its stance on fracking.
Scottish Conservative leader Ruth Davidson said the SNP administration had "leapt on its high horse" over shale gas extraction in Scotland.
But she claimed it had turned a blind eye to gas that was shipped to Scotland after being fracked abroad.
First Minister Nicola Sturgeon insisted the government was taking a cautious, evidence-based approach to the issue.
She told Ms Davidson it was a "bit rich" for her to challenge the SNP on energy given the UK government's support for new nuclear power.
And Ms Sturgeon insisted her government would not "play fast and loose with our environment".
The pair clashed at First Minister's Questions two days after the first giant tanker filled with shale gas from the US arrived at the Ineos chemical plant in Grangemouth.
Ineos says the shipments will safeguard the plant's future, and that of the 1,300 people who work there.
But the Scottish government did not send a representative to an event marking the tanker's arrival, saying only that ministers were "unavailable to attend".
It has imposed a moratorium on fracking and is currently awaiting the results of research into its potential impact, before carrying out a public consultation ahead of a final decision on whether it will be given the green light in Scotland.
Ms Davidson told MSPs it was time for Ms Sturgeon to "give the country some proper answers" over her position on the controversial process.
She argued that the government was attempting to kick the issue into the long grass, and of having "total double standards on this matter".
Ms Davidson added: "When it comes to shale gas in this country, they have leapt on their high horse, preached about a moratorium and boasted that they're the planet's best friend.
"But when the gas is poured into a tanker and shipped all the way across the Atlantic to our shores, then they turn a blind eye and hope that if they ignore it everybody else will too."
She said it was quite possible that shale gas in the rest of the UK would get the go ahead soon, if local communities back it.
If it does, she added, much of that gas would go to Grangemouth and end up in the national grid, powering many Scottish homes.
"So we could end up with a ban on Scottish gas but with Scottish homes reliant on English gas to keep the pipes warm," Ms Davidson said.
Ms Sturgeon said decisions about the import of shale gas to Grangemouth were taken by Ineos, which she described as an "extremely important company in the Scottish economy".
She added: "In terms of the issue of fracking in Scotland, I appreciate that the position of the Scottish Conservatives is to ride roughshod over local opinion, over environmental concerns, over the range of other concerns that have been raised.
"I think it's better to take the evidence-based, precautionary approach that this government is taking because we shouldn't play fast and loose with our environment.
"I know the Scottish Conservatives are a party controlled by London, but in the era of devolution I think it is right we take the decisions about fracking in Scotland here in Scotland and in our national parliament, and that's what we will continue to do."