NEW YORK (AP) — U.S. stocks are closing lower as worries about Greece rattle financial markets.

The Dow Jones industrial average dropped 125 points to close at 12,695, a loss of 1 percent.

Political parties in Athens resumed negotiations to form a government Monday. The uncertainty has raised concerns that if Greece leaves the currency union, bond traders may demand steeper borrowing rates from other troubled countries.

The Standard & Poor's 500 index dropped 15 points to 1,338. The Nasdaq sank 31 points to 2,903.

Treasury yields hit their lowest levels of the year as investors dumped riskier assets, and the euro sank to a three-month low against the dollar.

Five stocks fell for every one that rose on the New York Stock Exchange. Trading volume was 3.6 billion, lower than the recent average.