U.S. stocks fell 1% Monday amid concerns about European political uncertainty grow and another sign of a slowdown in the Chinese economy.

France's prime minister Nicolas Sarkozy came in second place in the first round of presidential elections Sunday. On Monday, Dutch Prime Minister Mark Rutte resigned.

The combination of political changes with a slowdown in China's manufacturing was enough to unnerve investors at the start of what will be a busy week on the economic and earnings front.

"The events over the weekend re-ignited concerns that the European community is going to have trouble working out a coordinated plan for austerity," said Douglas DePietro, head of equity sales trading at Evercore. "There's no economic data out of the U.S. today to thwart a sell-off."

In midday trading, the Dow Jones industrial average (INDU) dropped 138 points, or 1.1%. The S&P 500 (SPX) shed 14 points, or 1%, and the Nasdaq (COMP) lost 38 points, or 1.3%.

In the U.S., Wal-Mart (WMT, Fortune 500) dragged down the Dow after it was hit by allegations that top executives in its Mexican division attempted to conceal a widespread bribery scheme.