Others are fleeing Central and South America such as unrest in Venezuela

Most are Syrians fleeing the sixth year of conflict which has killed 250,000

Number that will rise to 100,000 in 2017 to help alleviate the worst global refugee crisis since World War II

Last year, the Obama administration pledged to accept 85,000 refugees from around the world in 2016, up from 70,000 last year

Asylum cases backlog hit 128,000 at the end of last year as US struggles to cope with double the number of requests in past five years

The federal government is struggling to cope with a huge surge of asylum cases during a global refugee crisis as the request backlog soars by 1,400 per cent in just five years.

Unrest in areas of the Middle East and South America has seen numbers of refugees requesting asylum more than double in the same period - pushing the U.S. Citizenship and Immigration Services, CIS, to breaking point.

Unable to cope, the backlog of cases has been steadily rising and by the end of 2015, there were more than 128,000 cases still pending, the agency's ombudsman Maria M. Odom, said in her annual report to Congress.

The federal government is struggling to cope with a huge surge of asylum cases during a global refugee crisis as the request backlog soars by 1,400 per cent in just five years (a Kurdish refugee mother and son from the Syrian town of Kobane)

Unfortunately, the situation is only set to get worse, the U.S. immigration agency's own watchdog said Wednesday, NBC reports.

Last year, the Obama administration pledged to accept 85,000 refugees from around the world in 2016, up from 70,000 last year.

That number will rise to 100,000 in 2017 to help alleviate the worst global refugee crisis since World War II.

The announcement sparked a backlash - particularly in the light of the terrorist attacks in Orlando, Florida, San Bernardino, California and most recently, the attack at a Turkish airport.

Critics believe that America should restrict the number of refugees in case would-be terrorists use the system to enter the country.

Republican presidential candidate Donald Trump has called for a ban on non-American Muslims coming the US - including Syrian refugees.

The situation is only set to get worse, the U.S. immigration agency's own watchdog said Wednesday. Last year, the Obama administration pledged to accept 85,000 refugees from around the world in 2016, up from 70,000 last year

Most refugees will be Syrians displaced by a brutal civil war, while others will come from Central and South America.

In Syria, the conflict, which entered its sixth year in March, has killed more than 250,000 people and displaced close to half the pre-war population of 23 million.

Many of Syria's refugees now live in dozens of sprawling encampments including in neighboring Jordan, which has taken in close to 640,000 migrants.

Millions of others have fled to Europe, making the dangerous passing to Turkey and across the sea to Greece from which they travel all over the continent.

Others hold out hope for the United States, but can be left waiting years as their asylum requests are processed.

The number of Venezuelans seeking asylum in the United States has also soared recently as the oil-dependent economy crashes and more of the middle-class flees.

In March 2016, Venezuelans climbed to second place among nationalities submitting asylum requests, with 1,345 applications during that month.

Most refugees will be Syrians displaced by a brutal civil war, while others will come from Central and South America (a Syrian refugee sits on a cement block as refugees and migrants line up to board a ferry after arriving on the shores of the Greek island of Lesbos)

Many of Syria's refugees now live in dozens of sprawling encampments including in neighboring Jordan, which has taken in close to 640,000 migrants

The South American country first cracked the top 10 asylum-seeking nations in February 2014 when a bloody, months-long street protest movement seeking to oust the socialist administration kicked off. But back then, amid the widespread jailing and harassment of opponents of President Nicolas Maduro, fewer than 100 Venezuelans per month sought asylum.

The number of applicants has accelerated sharply since December 2015, when the opposition scored a landslide victory in congressional elections - leading to more and more Venezuelans fleeing the country as an economic crisis marked by triple-digit inflation pulverizes salaries and widespread food and medicine shortages make life unbearable for many.

Obama may have promised to alleviate the world crisis by taking on more migrants, but the government has fallen far short of its own targets. As of April, State Department data showed that the United States had only accepted 1,285 of its 85,000 target.

Compounding the problem, the CIS is short of staff after they were forced to reassign asylum officers to its Refugee Affairs Division.

The agency is scrabbling to employ more officers but it will take time. Something many of the refugees simply don't have.

Odom's report also criticized CIS for not processing asylum applications for children from Central America and for the long delays in applications for naturalization for members of the US military and their families.