London: Russia`s incursion in Crimea is a "serious miscalculation" and Moscow could face far-reaching economic consequences unless a diplomatic solution can be found, British Foreign Secretary William Hague said on Sunday.
Hague said European countries could switch from using Russian gas to supplies from the United States or elsewhere in protest at Moscow`s actions.
He told BBC TV that a referendum in Crimea about whether to leave Ukraine scheduled for March 16 would come "ridiculously quick".
"The world will not be able to regard that as a free or fair referendum," Hague said.
He dismissed suggestions that Moscow was oblivious to the West`s anger at its actions in Crimea.
"I think they (the Russians) do care about the international reaction to what they`ve done. That reaction is strong," he said.
Hague said that unless a diplomatic solution could be found, "there would be far-reaching trade and economic consequences".
Possible measures such as visa freezes and travel bans would "be taken very seriously by the individuals concerned".
"Those are things over time which I think will mean this (the intervention in Ukraine) has been a serious miscalculation."
Although there have been no armed clashes yet, Hague warned that a lack of progress through negotiations would "bring the real danger of a real shooting conflict".