WASHINGTON — With the dramatic increase in Syrian refugees outpacing international funding to deal with the crisis, some aid agencies could be paralyzed within weeks, the U.N. high commissioner for refugees warned Wednesday.

Antonio Guterres said international humanitarian agencies face a grim dilemma if current conditions continue: either attend to only the most vulnerable of Syrians while others fend for themselves in squalid conditions, or focus on Syria at the expense of thousands of Afghan, Somali and Congolese refugees vying for the same assistance funds.

Now entering its third year, the Syrian conflict is seeping across borders and creating vast and growing refugee communities, quickly becoming the top threat to stability in an already volatile Middle East, Guterres told McClatchy in an interview in Washington, where he was meeting with Obama administration officials on Syria.

“There is a growing awareness that the Syrian crisis is not just another crisis,” Guterres said. “The scale, and especially the staggering acceleration, of the conflict and its humanitarian consequences really make it the most dangerous, the most complex and with the worst humanitarian need that we’ve had since the beginning of the century.”

The need has overwhelmed aid agencies, including some American nonprofit groups, Guterres said, forcing them into tough assessments of priorities and closer toward an acknowledgement that they simply cannot keep up with the wave of Syrian refugees, much less the millions of displaced who are still inside Syria.

“Some of (the aid agencies) might be paralyzed in the very short term, and even for others with a stronger capacity, activities will be strictly limited to core protection functions and to necessary life-saving measures for the most vulnerable people, which means that this population will not be supported as they deserve and as they need,” Guterres said.

The U.N.’s budgets for Syria were based on estimates that the number of refugees would reach 1.1 million by the end of June, but that mark was passed this month.

Guterres rattled off the somber math: In December, 3,000 Syrians fled per day. That number increased to 5,000 a day in January and 8,000 a day in February. In the past few weeks, there were times when 14,000 crossed the border in a single day.

Even if states that have pledged donations paid up, Guterres said, that money is considered gone already, earmarked for catching up on costs. And there’s no relief in sight – the United Nations is bracing for the possibility of 1 million refugees each for Turkey, Lebanon and Jordan by the end of the year.

“When you have such a large number of displaced people, it is not only terrible and unfair that they’re not supported, it’s also an additional risk of destabilization,” Guterres said.

Already, Lebanon’s population has shot up by 10 percent, with an influx of some 370,000 Syrians. Turkey has admitted more than 260,000 refugees, while Jordan is struggling to cope with more than 360,000 and is pleading for international help. There are at least 160,000 more Syrians who’ve fled to Egypt and other places in North Africa.

Governments from around the world pledged $1.5 billion in humanitarian funding for Syrians at a donor conference in January in Kuwait. The United States alone has contributed around $385 million in humanitarian aid to Syria, in addition to more than $100 million in “nonlethal” support such as radios and other communications equipment for the opposition.

Even so, Guterres said, it’s not nearly enough, with aid workers trying to operate with just 30 percent of the pledged funding.

“There has been a slow awakening to the dramatic impact of this crisis,” Guterres said.

“Until now, we have been living with the normal allocation of funds for traditional humanitarian budgets. But this, of course, is totally out of proportion with the dimension, the scale, and the acceleration of this crisis,” he said.

In addition, some of the wealthiest donors, such as Saudi Arabia and the United Arab Emirates, bypass the international process and funnel resources directly to groups on the ground. They’re not only traditionally mistrustful of the United Nations, but they’re also trying to boost the popularity of their own charities and the rebel factions they’re supporting, especially those run by Islamists.

The Islamists’ noted success in aid delivery – some groups, Guterres said, were using long-established community service networks – makes it all the more important to increase international support of the U.N.-led humanitarian effort, which strives to be nonpartisan and nonreligious.

Guterres said the Syrian crisis is no different from any other protracted conflict in which extremist forces are pushed to the forefront as the central authority evaporates.

“It is clear that whenever you have a conflict that lasts so long, it tends to benefit those groups with more extreme positions,” Guterres said. “It’s a universal law, and obviously it’s happening in Syria.”

The conflict, he said, has become “a magnet” for attracting fighters from throughout the region – and even from his own continent. Guterres, a former prime minister of Portugal, recalled a recent meeting with the interior minister of the European Union in which officials expressed alarm at the number of Europeans of Syrian heritage who’ve joined the fight.

“The risk of the Syrian crisis triggering an explosion in the Middle East is a real one,” Guterres said. “This is not only a humanitarian question. This is becoming a threat that cannot be overestimated for regional peace and stability and, to a certain extent, for global peace and stability.”