Four bodies have been found in the Arizona desert, likely migrants attempting to cross into the United States. Local authorities found the bodies about 70 miles north of the U.S.-Mexico border, deep in the harsh Sonoran Desert.

"It is probable that they are immigrants attempting to cross into the U.S.," said Victor Brabble, a spokesperson for U.S. Customs and Border Protection. "However, we don't have enough to draw a conclusion on it now."

More than 100 people die each year attempting to cross the Arizona desert, a number that is likely to climb if the bipartisan immigration bill currently being debated in the Senate ultimately passes both houses of Congress.

While the bill will offer a path to citizenship for many of the 11 million undocumented immigrants currently living in the country, it does little to ease the process for prospective immigrants and pours money into increased border security.

Republicans say it is necessary to secure the border, and many will not support the immigration reform bill without that concession. Opponents say it is a waste of public money and will force migrants to use more dangerous and deadly paths into the country, increasing the likelihood that more people will die in the desert.

But the current provisions of the bill aren't enough for many Republicans. A new amendment proposed by Republicans John Hoeven of North Dakota and Bob Corker of Tennesse would add 20,000 more border patrol agents, $3.2 billion in technological and equipment upgrades and install 700 miles of fencing along the border.

"If you believe in strong border security, the Corker-Hoeven amendment practically militarizes the border," tweeted Lindsey Graham of South Carolina, one of the Republican members of the Gang of Eight responsible for creating the original bill.

Democrats are willing to go along with the amendment, as they believe it will allow the full bill to pick up the support of perhaps a dozen more Republicans.

A vote on the amendment is scheduled for Monday.