Stocks came under pressure on Friday as the situation in Eastern Europe kicked up a few notches.

With Russia’s near 300-truck-long “humanitarian” convoy parked near the Ukrainian border, British journalists reportedly witnessed a convoy of Russian military vehicles — including 23 armored personnel carriers — cross into Ukraine. Ukraine said it destroyed part of this convoy. Russia denies sending anything over in the first place.

The renewed escalation of tensions has stocks on the slide again, threatening to put an end to the two-week-long rebound the market had been enjoying. The situation on the ground remains in flux with Ukrainian border guards apparently inspecting Russia’s aid convoy in preparation of the move across the border. But confusion reigns.

So further escalation looks likely before this is all done, which comes at a time of vulnerability for the economy and markets.

Stocks at a Turning Point

Click to Enlarge For stocks, the day’s headlines have pushed the major averages back below critical technical support levels with the small-cap Russell 2000 Index moving back below its 200-day moving average, a level it has been mired below since late July.

Breadth measures also suggest that the situation is on tenterhooks. The percentage of S&P 500 stocks that are in uptrends has moved down near 71% — a drop from a high of around 85% back in mid-July — but still is above the lows of 65% and 62% hit during the February and April selloffs.

The Russia situation could be the catalyst the market needs to get a nice, deep oversold condition that it can rally out of.

Bond Market Nervousness

Click to Enlarge Over in the bond market, the yield on 10-year Treasury notes has dropped to 2.3% — levels that haven’t been seen since June 2013 — as traders seek a safe haven. This is a big deal, since it nearly reverses the back up in yields seen during last year’s “taper tantrum” related to former Federal Reserve Chairman Ben Bernanke’s warning that the QE3 bond purchase program would soon start being rolled back. Now that we’re just two months away from QE3 ending entirely, the drop in yields suggests that the economy and the markets won’t be able to handle it.

In fact, the relationship between the drop in yields (and the rise in bond prices) vs. stock prices is falling at a pace not seen since the summer of 2011 — just ahead of the August 2011 market wipeout that, to date, has been the biggest correction of this bull market so far. If the tensions between Kiev and Moscow worsen, bond yields should continue to drop (as prices rise) with stocks suffering as a result.

The Global Economy

Click to Enlarge And while the economic data here at home has been strengthening, with signs of tightening in the job market, it hasn’t been the same story overseas. Economic releases out of Europe, China, and Japan have all disappointed this week. And this slowdown has been corroborated by the weakness we’ve seen in economically-sensitive commodities such as crude oil and copper this week.

West Texas Intermediate Crude dropped to $95.50 a barrel on Thursday, a low not seen since January. Copper, as represented by the iPath Dow Jones-UBS Copper Subindex Total Return ETN (JJC) returned to June levels.

The problem is that economic sanctions against Russia could boomerang back to Europe and deepen the Eurozone’s economic woes. This comes despite the fact that the European Central Bank just cut its policy rate into negative territory. Moscow’s decision to ban food imports is deepening Europe’s deflation problem, a sign that Russia understands exactly where it can apply maximum leverage.

As a result, the iShares S&P Europe 350 Index (IEV), shown above, has dropped below its 200-day moving average in a significant way for the first time since May 2012.

What Comes Next, And How to Play It

Click to Enlarge According to analysts at Stratfor, while Ukraine’s forces have made progress against pro-Russian separatists, they are spread thin and are vulnerable to a counterattack should Russian forces (as is feared) make an overt push into the territory.

Another potential flashpoint comes from reports, cited by Stratfor, of the alleged separatist capture of pro-Kiev fighters planning an attack on Russia’s humanitarian convoy. Tensions are rising as Russia keeps stockpiling forces on its side of the border with more than 20,000 troops estimated along with airborne forces, battalion task groups, and air defense systems.

The most direct way to play a worsening of the situation is by betting against Russian and European stocks. I’ve already recommended the Direxion Dailly Russia Bear 3x Shares (RUSS) to my Edge clients on July 17, with the position up 4.1% after trimming profits at a 10% gain back on July 30. Another idea would be the ProShares UltraShort FTSE Europe (EPV).

Anthony Mirhaydari is founder of the Edge and Edge Pro investment advisory newsletters, as well as Mirhaydari Capital Management, a registered investment advisory firm. As of this writing, he had recommended RUSS to his clients.