Foreign Secretary William Hague has said that Nato has "not seen the evidence" of Russian forces pulling back from the Eastern border of Ukraine.
Nato foreign ministers have met in Brussels to discuss the Alliance’s response to Russia’s seizure of Crimea.
Hague also stated that Nato needed to give "reassurance and confidence to Eastern allies," with the UK already promising "fighter planes to the Baltic", among other measures.
An unusually frank Nato Secretary General issued an unequivocal warning on the course of events should Russia attack Latvia or Estonia.
The West responds with sanctions and closer political ties with Ukraine as Russia's President seals the annexing of Crimea to much fanfare.
Supporters of the controversial fracking industry believe shale gas could be America's most potent weapon in the stand-off with Russia.