The U.S. equity market plunged Friday as investors deeply concerned about European uncertainty.

Despite Facebook's IPO attracted eyes of the market, European concerns still drove the equity market on Friday. Alexis Tsipras, the leader of Greece's Syriza party, boasted to the market that Europe would never cut off Greece financially as it would mean an implosion of the entire region.

However, there were rumors saying that European Union and European central bank are planning emergency measures of letting Greece exit euro zone.

Meanwhile, Spain became another headline for investors after Greece. The rating agency Moody's downgraded 16 Spanish banks' long-term credit ratings late Thursday. On Friday, there was some vague speculation about Spanish government's imposition of a new short sale ban.

Spain's bond yield continued rising sharply in recent trading days, suggesting deep concerns from the market.

Moreover, investors now focused on the upcoming Group of Eight meetings this weekend. The Group of Eight officials are expected to offer support for the EU "to make sure monetary leaders in Europe try to work with distressed players like Greece for as long as possible."

In the U.S., Facebook issued 421 million shares on its initial public offering Friday at 38 dollars apiece, raising more than 16 billion dollars, which is the largest IPO among all internet companies.

The world's largest online social network closed at 38.37 dollars per share on its first trading day on Nasdaq stock market, up 0.97 percent from its IPO price of 38 dollars.

The Dow Jones industrial average fell 73.11 points, or 0.59 percent, close at 12,369.38. The Standard & Poor's 500 was down 9. 64 points, or 0.74 percent, to 1,295.22. The Nasdaq Composite Index lost 34.90 points, or 1.24 percent, to 2,778.79.

As for other markets, U.S. crude oil price dipped further Friday and closed under 92 dollars a barrel for the first time since October, as concerns about Greece's exit from euro zone kept weighing heavily.

Light, sweet crude for June delivery slipped 1.08 dollars, or 1. 17 percent, to settle at 91.48 dollars a barrel on the New York Mercantile Exchange.

For this week, it declined 4.65 dollars, or 4. 84 percent, registering a third straight weekly drop. In London, Brent crude for July delivery also declined and last traded around 107 dollars a barrel, also heading to a third consecutive weekly decline.

The U.S. dollar traded mixed against major currencies in late New York trading Friday after 14 consecutive rallies.

The euro rebounded against the dollar despite the European debt concerns still weighed on the market.