UPDATED 8/19/2013 at 7:45 a.m.
Masked gunmen stormed two civilian minibuses carrying Egyptian police Monday, fatally shooting 25 officers in Northern Sinai, NBC News reports.
The police conscripts were on their way back from vacation, NBC reports, when the attackers ordered the officers down and opened fire with machine guns.
"Militants ambushed bus carrying off-duty policemen in Egy's N.Sinai,killing 25 of them EXECUTION-STYLE.Egypt will hunt and kill terrorists," the Egyptian Cabinet tweeted Monday morning.
The attacks come after at least 38 Muslim Brotherhood supporters who were being kept as prisoners were killed late Sunday after authorities said they attempted an escape outside Cairo, NBC News' Ayman Mohyeldin reported. Police responded with gunfire into a transport vehicle after prisoners at Abu Zaabel prison took two senior officials hostage, according to Mohyeldin.
Members of the Anti-Coup Coalition, an anti-military group, contradicted the official account of events, saying the prisoners were in a truck being transferred to the prison and were killed with live ammunition and tear gas through the windows, NBC News reported.
In addition to canceling an upcoming joint-military exercise, the Obama administration was considering canceling the shipment of 12 Apache helicopters sold to the Egyptian military for $820 million in 2009. Thursday, President Obama announced that he would cancel the Bright Star military exercise but stopped short of calling the violence in Egypt a coup, and did not say that he would cancel foreign aid to the country.
The United States gives more than $1 billion in aid to Egypt and a growing number of Senators have called for the president to cancel all of it. Republican Kelly Ayotte of New Hampshire and Democrat Jack Reed of Rhode Island—both of whom are members of the Senate Armed Services Committee—argued in favor of cutting off the funding on on Meet the Press Sunday.
"The acts of the last few days by the Egyptian military are completely unconscionable and I do believe we have to change our aid," Reed said on the show. "I think also we have to have included in the legislation a national security waiver because we have to give the president not only the responsibility to deal with the government of Egypt but also flexibility."
On Friday, Republican Senator John McCain of Arizona and Republican Lindsey Graham of South Carolina released a joint statement condemning the violence in Cairo and urging Obama to suspend assistance. "It is neither in our long-term national interest nor consistent with our values and laws to continue providing assistance at this time to Egypt’s interim government and military," the statement read.
But other voices urged caution in withdrawing all aid from Egypt and risk losing leverage with authorities.
"We have to be mindful that the leverage is limited," said Ambassador Dennis Ross Sunday, adding that Saudi Arabia and the United Arab Emirates would replace the funds canceled by the U.S. "And if you take the step and you cut it off, what do you have then?"
In a speech Sunday, Egyptian military chief Abdel Fattah al-Sisi said that “there is room for everyone in Egypt," but government leaders like Prime Minister Hazem el-Beblawi have argued in favor of a ban on the Islamist political party.
The country's cabinet was meeting Sunday to discuss a way out of the security crisis enveloping Egypt. Four days after clashes began, curfews remain in effect and violence has continued with as many as 800 people killed, according to Reuters. Protesters fought with the military on Saturday while under siege in a mosque in central Cairo. The mosque was eventually cleared and many of those inside were taken into custody.