The surge of refugees fleeing Syria and other war-torn regions is putting immense pressure not only on Europe but also the United States, as the Obama administration faces calls to take a more active role in the humanitarian crisis. 

At the same time, some lawmakers on Capitol Hill are warning that loosening immigration rules to take them in would pose a serious security risk. For the Obama administration – and the one that succeeds it – there are no easy answers. 

To be sure, many of the millions fleeing civil war and terror come from countries with a strong Islamic State presence, and lawmakers have warned that applicants must be properly vetted for terror ties. But the images emerging from Europe over the past several weeks underscore the humanitarian imperative -- photos of a drowned boy's body washing up on a Turkish beach, of clashes in Hungary over shuttered train routes to Western Europe, of an abandoned truck filled with refugees' corpses in Austria.  

The pace and scale of displacement, and the extreme measures refugees are taking to escape their own battered homeland, has quickly made Syria’s problem everyone’s problem. 

“Not only are Syrians resorting to desperate measures to seek a better life for themselves and their families in Europe, but they are dying in the process,” International Rescue Committee President David Miliband said in a statement Wednesday. IRC, a global humanitarian aid group helping with refugee relocation, also renewed its calls for America to open its borders to refugees.

White House Press Secretary Josh Earnest said Thursday that the images surfacing from Europe are a “stark reminder” of the “tragic" toll from the Syrian civil war. Asked what the U.S. might be doing to respond, he stressed the U.S. has given $4 billion toward humanitarian assistance and is supporting U.N. refugee efforts but -- on the question of bringing more Syrian refugees to the U.S. -- said, "At this point, I don't have any announcements along those lines." 

As it stands, Syria's neighbors are in danger of buckling under the burden of housing, feeding and caring for millions of Syrian refugees. Lebanon, Jordan, Egypt, Turkey and Iraq have absorbed an estimated 4 million refugees so far. The others are mostly heading for Europe. 

But in the U.S., the Obama administration has been criticized by lawmakers and humanitarian groups for not doing enough, particularly for Christians and other religious minorities stuck inside blood-soaked Syria.

“The United States has a moral obligation to assist countries that are hosting Syrian refugees, but we also have a national security interest in maintaining stability in this critical region,” Sen. Dick Durbin, D-Ill., argued in a letter earlier this year to Obama. “Moreover, at this delicate moment in relations between the United States and the Arab world, offering safe haven to more Syrians refugees will send a positive signal about our concern for the suffering of innocent Syrian civilians.”

Nina Shea, a fellow with the Hudson Institute and director of the Center for Religious Freedom, told FoxNews.com that immediate measures need to be implemented to help Christians in the region looking for ways to escape and places to go. While Shea says Christians are in greater danger in Iraq, the situation in Syria is growing graver by the day.

“The men are killed and the women and children are enslaved,” she said.

The Obama administration recently indicated it might consider the use of “parole” for some Syrian nationals to supplement existing refugee resettlement efforts.

Parole is an emergency move the government can take for “urgent” humanitarian relief for foreigners who would otherwise be ineligible for entry or put on a lengthy waiting list. The temporary passes come with an expiration date though many argue the U.S. immigration system already is so bloated and dysfunctional, any type of enforcement would be difficult. 

In a recent letter to a Senate Judiciary subcommittee, a USCIS official said the agency decided in 2013 "that establishing such a program was not warranted” for Syrians. But the official added: “However, as the situation continues to evolve and USCIS continues to engage with stakeholders, USCIS may reconsider the use of parole for certain Syrian nationals.”

The USCIS did not return a request for comment from FoxNews.com. If the agency did opt to use "parole" for Syrians, that would be on top of other ways refugees already are being processed, albeit at relatively low levels. In the U.S., 1,500 Syrians have been granted asylum as of March. And nearly 1,000 refugees were resettled in the U.S. this year, according to the State Department. The Obama administration indicates it plans to bring in more, and external pressure is growing. 

The United Nations High Commissioner for Refugees announced in December that Western nations had pledged to accept 100,000 Syrian refugees in 2015 and is calling for 130,000 Syrians to be resettled by the end of 2016.

The IRC has repeatedly urged the U.S. to allow in at least 65,000.

“By historical standards, the United States should be committing to take around 65,000 – or 50 percent -- of those identified by the United Nations for resettlement by the end of 2016,” Miliband wrote in an op-ed for The Washington Post.

But not everyone is on board with the idea, warning there’s potential for the Islamic State and other militant fighters to infiltrate the resettlement process.

Rep. Peter King, R-N.Y., who chairs the House Homeland Security Counterterrorism and Intelligence Subcommittee, said at a hearing while he believes “the vast majority of Syrian refugees do not have ties to terror groups” he does have “a number of concerns, not the least of which is the lack of on-the-ground intelligence necessary to identify terror links." 

Rep. Michael McCaul, House Homeland Security Committee chairman, wrote President Obama a letter citing concerns over plans to resettle Syrians in the U.S.

“Despite all evidence towards our homeland’s vulnerability to foreign fighters, the administration still plans to resettle Syrian refugees into the United States,” McCaul, R-Texas, said. He later added, “America has a proud tradition of welcoming refugees from around the world, but in this special situation the Obama administration’s Syrian refugee plan is very dangerous.”

Anne Richard, U.S. assistant secretary of state for population, refugees and migration, disagrees. She recently insisted on NPR that "these cases are the most carefully vetted of any travelers to the United States, and nobody comes in without having a Department of Homeland Security interviewer agree that they are, in fact, bona fide refugees." 

To date, 250,000 Syrians have died and 11 million more have been displaced, making Syria the largest single source of refugees in the world, according to Antonio Guterres, the U.N. High Commissioner for Refugees. 

In Europe, leaders remain divided over how to handle the surge of refugee-seekers. British Prime Minister David Cameron argued the best solution is to bring peace to the Middle East.

“I don’t think there is an answer that can be achieved simply by taking more and more refugees,” he said.

Hungarian Prime Minister Viktor Orban, who has come under fire for urging caution, said Europe’s focus needs to be on protecting its borders, not opening them up.