Brent crude oil prices suffered dramatic losses after the announcement of a framework agreement on oil-rich Iran's controversial nuclear program.

Brent prices were off more than 3 percent to $55.17 per barrel as markets weighed prospects of Iran re-entering the global oil marketplace.

A framework agreement announced Thursday in Switzerland outlines Iran's drawback from the brink of developing a nuclear arsenal through long-range commitments and verification measures. In exchange, Iran can expect some relief from international sanctions.

"Iran will receive sanctions relief, if it verifiably abides by its commitments," a document on the deal from the U.S. State Department read.

Iran in 2011 exported around 2.5 million barrels of oil per day. Exports under a sanctions protocol adopted in November 2013 average around 1.4 million bpd. Iranian Oil Minister Bijan Zangeneh said last week that, once sanctions are lifted, more Iranian oil would find its way to the global market "in a short matter of time."

Negotiators said Thursday's agreement was only a tentative step toward a final arrangement expected later this year. Congressional leaders in the United States, meanwhile, said they had questions about the deal.

"My longtime concerns about the parameters of this potential agreement remain, but my immediate concern is the administration signaling it will provide near-term sanctions relief," House Speaker John Boehner, R-Ohio, said in a statement.

Even without Iranian oil, markets are titled heavily toward the supply side in part because of the increased oil production from the United States. Demand, meanwhile, is tepid in a global economy showing few signs of robust growth.

The U.S. Labor Department said Friday hiring was sluggish in March, with employers adding only 126,000 jobs. That's the fewest in more than a year and data show hiring in the mining and extractive industries was among the hardest hit.

The national unemployment rate remained at 5.5 percent for March. For mining and the oil and gas sector, the rate was 8 percent.

U.S. markets are closed because of Good Friday. The price for West Texas Intermediate, the U.S. benchmark, was last off more than 1 percent to sell for $49.55 per barrel for May delivery.