NEW YORK (AP) — The stock market extended its slide yesterday after investors couldn't shake their concerns about European countries' big debt loads.

The Dow Jones industrial average ended down about 59 points to put its two-day drop at 284. The Dow halved its loss by the close but finished off its high of the day. Treasury prices rose and pushed down interest rates in the bond market for a second day.

A drop in the euro and a rise in the dollar continued to ram markets around the world. The stronger dollar hurts US stocks by cutting into profits of US companies that do business abroad. A higher dollar also hurts commodity prices by reducing demand from foreign buyers.

Investors are concerned that a $144 billion aid package for Greece won't be adequate to keep debt problems in Europe from spreading. There were also questions about whether the bailout would amount to more than a short-term fix for Greece. Investors don't want the trouble in Greece to spill to other countries and disrupt a global rebound.

Swings in global stock markets have intensified in the past week. Yesterday was the sixth time in seven days the Dow moved by more than 100 points. Investors have questions about Greece but they're also awaiting the government's April jobs report on Friday and monitoring Washington's overhaul of the rules that govern financial companies.

The problems in Greece are rattling the market partly because they are reminiscent of the sub-prime mortgage crisis in the US that at first appeared contained. That bad debt cascaded through the world's financial system and pushed the US economy into recession at the end of 2007.

German Chancellor Angela Merkel yesterday encouraged lawmakers in Berlin to rush the approval of Germany's share of the Greek rescue plan by tomorrow. Analysts say delays could bring more upheaval to global markets. Investors fear that if a tourniquet for Greece's financial problems doesn't hold, it would be harder to help larger countries like Spain and Portugal that also face big deficits. Moody's Investors Service warned on Wednesday that it could cut Portugal's credit rating two notches in the next three months. Standard & Poor's cut Portugal's credit rating last week.

Adam Gould, senior portfolio manager at Direxion Funds in New York, said the uncertainty about what will happen in Europe is keeping investors from buying dips in the market the way they have for most of the 14-month climb in stocks.

"This is really a story that has the market spooked," Gould said. "First it was Greece. Now it's Spain and Portugal."

Fixing Greece's financial problems won't be easy. Riots erupted in Athens yesterday over tax hikes and government spending cuts that the International Monetary Fund and other European nations are requiring as part of the bailout. Three people were killed in the protests.

The problems of heavy government debts are a big test for the euro. Sixteen countries use the common currency. The euro fell against the dollar, sliding as low as $1.2805 in New York. That was its weakest level since March 2009.

The Dow fell 58.65, or 0.5 percent, to 10,868.12. It had been up as much as 20 points and down nearly 112 points.

The Dow is down 2.5 percent in two days, its steepest back-to-back drop in three months.

The broader Standard & Poor's 500 index fell 7.73, or 0.7 percent, to 1,165.87, while the Nasdaq composite index fell 21.96, or 0.9 percent, to 2,402.29.

Bond prices rose. The yield on the benchmark 10-year Treasury note fell to 3.54 percent from 3.60 percent late Tuesday.

Gold rose. Crude oil fell $2.77 to $79.97 per barrel on the New York Mercantile Exchange.

Kevin Mahn, chief investment officer at Hennion & Walsh in Parsippany, New Jersey, said the debt problems are severe but not new. He said investors had been looking for an excuse to sell stocks after the market's steep 14-month climb. Mahn expects the big back-and-forth moves will continue.

"I think it's going to be more of an extended pause than a correction," Mahn said.

Investors looking for continued signs of a US rebound found another encouraging sign on employment yesterday. Payroll company ADP said private employers added 32,000 jobs last month. That was slightly above expectations.

The ADP report is seen an early indicator of the government's monthly employment report, though there are often wide variations because the ADP only accounts for private-sector jobs.

The Labor Department is expected to report tomorrow that the unemployment rate was unchanged at 9.7 percent last month.