The Dow Jones Industrial Average (^DJI -0.79%) was down 1833 points, to 16,138, at 1:30 p.m. EST as Russia's actions in Crimea spook investors around the world, lowering markets and raising commodity prices.. The S&P 500 (^GSPC -0.66%) was down 16 points to 1,843. Brent crude prices were up 1.9% to $111.15.

All 30 companies that make up the Dow Jones Industrial Average are down today as the situation in Ukraine worsens. Over the weekend, Russian troops took control of the Crimea region of the former Soviet territory. This has sparked an exodus of money out of Russia, with the Russian ruble weakening 2% against the U.S. dollar, a massive move in the currency markets.

Source: Bloomberg.

In response, the Russian central bank today announced a surprise short-term lending rate increase of 150 basis points, from 5.5% to 7%. The combination sent the Russian Micex Index down 11%.

Source: Bloomberg.

Notable large caps leading the Russian stock market's decline are: Sberbank, down 12%; Gazprom, down 12%; Mechel, down 8%; and Yandex, down 15%.

As tensions continue expect oil prices to rise. We will have to wait and see how the West will respond to Russia's actions and how the situation unfolds. I could speculate for hours as to what might happen, but the question to ask yourself is, "Does this change my investing strategy?" The answer should be no.

I hope that cooler minds will prevail and that the tensions in Ukraine will deescalate. Until then, who knows where the stock market will go. The stock market has looked overvalued for some time, leading me to suggest it's a good time to build up some cash so you are able to invest when opportunities arise.

The Motley Fool has always taught that Foolish (capital "F") investors don't invest in the broad market. We invest in great companies at good prices, continue to educate ourselves, and hold on to our great companies over the long term. The market will fluctuate (sometimes massively), but great companies will win out over the long run.