By Josh Smith

KABUL (Reuters) - Afghanistan's continued descent into crisis is forcing the country to increasingly rely on humanitarian aid that can only provide short-term relief while leaving the underlying problems unsolved, international officials acknowledged on Saturday, even as they launched a request for $550 million in new funding.

Amid rising violence, economic stagnation, and social upheaval, the United Nations estimates at least 9.3 million Afghans, or nearly a third of the population, will need humanitarian assistance in 2017, a 13 percent increase from last year.

While praising the humanitarian workers who provide vital care around the country, Swedish ambassador to Afghanistan Anders Sjoberg said the continued reliance on their services is a sign of broader failures.

"Let us acknowledge that we've been doing this work in Afghanistan for too long," he said at an event with international and Afghan officials in Kabul on Saturday. "This is a failure in itself. Humanitarian aid is not short-term anymore, it has unfortunately become a Band-Aid for the unresolved conflict."

Since even before a U.S.-led military operation toppled the Taliban regime in 2001, international organizations have helped provide both more short-term humanitarian aid designed to address the most pressing and life-threatening problems, as well as long-term development support.

But last year saw record increases in the number of people displaced by fighting, with at least 626,000 additional people fleeing their homes, compared to around 70,000 in 2010, when the international military effort was at its height.

The number of refugees returning - in many cases forcibly - to Afghanistan from neighboring countries like Pakistan and Iran also spiked dramatically, from 181,000 in 2015 to at least 618,000 in 2016, according to the U.N.

That has led the humanitarian community in Afghanistan to request $550 million to help an expected 5.7 million of the most vulnerable people in 2017, the highest amount of funding requested since 2011.

"We need to link humanitarian and long-term development aid much more effectively and we must not allow humanitarian aid to contribute to cementing the conflict," Sjoberg said, noting that the crisis highlights the need to find a peaceful resolution to the conflict.

Mark Bowden, the U.N.'s humanitarian coordinator, told Reuters in a recent interview that the prolonged violence has created a "vicious cycle" in which Afghanistan struggles to address the root causes of problems like economic malaise, limited access to medical care and education, and malnutrition.

(This version of the story corrects the year when displaced persons levels were at 70,000)

(Reporting by Josh Smith; Editing by Shri Navaratnam)