Alan Gomez

USA TODAY

The revelation that the suspected New York City bomber was born in Afghanistan before becoming a U.S. citizen prompted Republicans to attack the U.S. government's immigrant screening process.

Following the apprehension of Ahmad Khan Rahami, who immigrated with his family to the U.S., Republican presidential nominee Donald Trump and GOP lawmakers said the government doesn't know enough about people from countries with terror connections — such as Afghanistan, Iraq, Syria and Somalia — to allow their continued access into the U.S.

"These attacks, and many others, were made possible because of our extremely open immigration system, which fails to properly vet and screen the individuals or families coming into our country," Trump said during a campaign stop in Estero, Fla. "Immigration security is national security."

Senate Majority Leader Mitch McConnell, R-Ky., took to the Senate floor Monday to discuss national security threats facing the U.S. from terrorists abroad and those who have entered the country. Sen. Marco Rubio, R-Fla., said the attacks were a reminder that the country needs to "enhance the vetting of immigrants to ensure we are not granting citizenship or refugee status to terrorists."

Rep. Jeff Duncan, R-S.C., said the U.S. must “indefinitely suspend” all forms of immigration from countries classified as terrorist safe havens by the State Department. Rep. Steve King, R-Iowa, said on Twitter that the country's news media will continue featuring "terrorist attacks followed by press conferences featuring their enablers."

More on the NYC-area bombings:

Those sentiments were compounded by a Department of Homeland Security internal audit released Monday that found 858 people were mistakenly granted U.S. citizenship even though they had deportation orders pending against them. The audit blamed DHS and the FBI for failing to digitize all their fingerprint files, which allowed people to apply for citizenship using fake identities.

Rep. Michael McCaul, R-Texas, chairman of the House Homeland Security Committee, has long argued that the federal government doesn't have the tools to properly vet people coming from countries with ties to Islamic extremism. He pointed to Monday's DHS audit as proof.

"In order to prevent individuals like these from slipping through the cracks, we must quickly digitize old fingerprint cards and bring our immigration process into the 21st century," he said.

Obama plans big boost in refugees the U.S. will accept over next year

Many Democrats have criticized Trump for scapegoating immigrants with his calls to build a giant wall along the southern border and temporarily halt all immigration from Muslim countries.

But after the shooting rampage in San Bernardino, Calif., by a U.S. native and his Pakistani wife, who apparently radicalized him, Democratic Sen. Dianne Feinstein of California pushed a bill to restrict people entering through a special visa waiver program if they had visited Iraq or Syria in the previous five years.

In the immediate aftermath of the Paris attacks last November, when some believed the perpetrators included Syrians who entered France as war refugees, some Democrats questioned whether the U.S. should halt its Syrian refugee program. None of the attackers was confirmed to be Syrian, but the worry was enough for some, like Sen. Charles Schumer, D-N.Y., to suggest a "pause" in the Syrian refugee program to ensure the system was working.

And on Monday, Democratic presidential nominee Hillary Clinton said she has long supported improvements to the country's ability to vet immigrants. "I am absolutely in favor of, and have long been an advocate for, tough vetting," she said.

All the while, the Obama administration has defended its ability to screen foreigners trying to enter the U.S. Just last week, the administration announced its plan to increase the number of refugees to 110,000, up from 85,000 this year and 70,000 a year from 2013 through 2015.

In the past year, DHS has repeatedly defended its screening procedures: Refugees must undergo in-person interviews abroad and have their names run through federal terrorism and criminal databases. Syrian refugees go through more screening, where federal officials check their backgrounds against classified information, a process that can take up to two years to complete.

DHS Secretary Jeh Johnson has acknowledged that the system could be improved but told USA TODAY last November that the system was sound.

"We now do a better job of connecting dots, consulting all the right databases and systems that we have available to us," he said.

Contributing: Erin Kelly and Donovan Slack in Washington