President Barack Obama has been under fire since he announced a historic nuclear deal with Iran on Tuesday.

Following weeks of negotiations in Vienna, the U.S. and five other world powers reached the landmark agreement which places limits on Iran's nuclear program for the next 10 years and its research for the next 15 years. In exchange, the world powers agreed to ease economic sanctions on Iran.

"Today after two years of negotiation the United States together with the international community has achieved something that decades of animosity has not: a comprehensive long-term deal with Iran that will prevent it from obtaining a nuclear weapon," said the president from the White House, reports CNN.

According to Obama, the deal with Tehran ensures that "every pathway to a nuclear weapon" is cut off.

"We have stopped the spread of nuclear weapons in this region," he said in his speech, which was also televised in Iran, reports NBC News.

However, shortly after the announcement, Republicans and Israel supporters blasted the deal. Israeli Prime Minister Benjamin Netanyahu also condemned the agreement as a "historic mistake" that has given Iran a "sure path to nuclear weapons."

Several Republicans running in the 2016 presidential race have seized the moment to criticize Obama and the deal. According to Texas Sen. Ted Cruz, the deal will be used to sponsor "radical Islamic terrorism."

"Today, the international community led by the United States has agreed to not only legitimize and perpetuate the Iranian nuclear program, but also to further arm and enrich the brutal theocratic regime that has oppressed the Iranian people for more than thirty years -- a regime that is wrongfully holding United States citizens captive, that is sponsoring radical Islamic terrorism across the globe, and that regularly promotes the destruction of both Israel and America throughout its streets," said Cruz in a press release.

Likewise, House Speaker John Boehner said the agreement will "hand a dangerous regime billions of dollars in sanctions relief while paving the way for a nuclear Iran," reports CNN. He added that if "it's as bad a deal as I think it is at this moment, we'll do everything we can to stop it."

On the other hand, Democrats and foreign policy analysts have voiced support for the plan.

"This deal keeps Iran's nuclear program confined, monitored from every angle, with narrow maneuvering room," wrote Jacqueline Shire, a former member of the U.N. Panel of Experts on Iran, in an opinion piece for CNN. "It also provides a path for Iran to engage constructively with the world, more necessary now than ever before."

Rep. Joaquin Castro, D-Texas, also praised the agreement and said the deal places the U.S. and allies in an improved peace and security position.

"Initial readings of the deal's text indicate it contains stringent accountability measures that protect against the possibility of a nuclear-armed Iran," said Castro in a statement. "Congress will now have a say in how the United States proceeds, and I hope that my colleagues will take time to thoroughly and thoughtfully evaluate the details of the agreement our negotiators achieved."

Sen. Bob Menendez, D-N.J., said Congress needs to fulfill its duties and review the nuclear deal.

He added, " But I'm concerned that the deal ultimately legitimizes Iran as a threshold-nuclear state. I'm concerned the redlines we drew have turned into green-lights; that Iran will be required only to limit rather than eliminate its nuclear program, while the international community will be required to lift the sanctions, and that it doesn't provide for anytime-any-place inspections of suspected sites. The bottom line is: The deal doesn't end Iran's nuclear program - it preserves it."