April 3 (Bloomberg) -- With Russian forces massed near the country’s border with Ukraine in a high state of readiness, NATO leaders warned that any incursion across the frontier would be a “historic mistake.”

The presence of as many as 40,000 soldiers along Ukraine’s eastern border is fueling concern that Russia is poised to invade on the pretext of protecting Russian-speaking inhabitants of eastern and southern Ukraine. Backed by state-run media, President Vladimir Putin says the Kiev-based government is influenced by anti-Russian extremists and hasn’t done enough to stop them from persecuting Russian-language speakers.

“We have seen a very massive Russian military buildup along the Ukrainian borders,” North Atlantic Treaty Organization Secretary General Anders Fogh Rasmussen said yesterday after a two-day meeting of alliance foreign ministers in Brussels. “We also know that these Russian military armed forces are at very high readiness.”

Ukraine acting President Oleksandr Turchynov said on state- run TV channel UT-1 that Russian aggression is pushing Ukraine toward affiliation with NATO. He said he doesn’t “rule out”

joining NATO if Russia continues to act in the same way. The border situation remains “tense,” he said, calling Russian pledges to pull back troops “a lie.”

Russia pressed Ukraine to disarm nationalists it says are oppressing its compatriots there, echoing comments it made in the run-up to its military occupation of Crimea and its annexation last month following a Kremlin-backed referendum.

Ukraine’s government denies that Russian speakers are at risk.

David Fuller's view

Is this just a tactical, political bluff by NATO?

Has an emboldened Putin decided not to make the tactical withdrawal from Ukraine’s Eastern border that he mentioned only a few days ago?

I do not know but this is a potentially confrontational situation which stock markets are not currently reflecting.