"Syria and its neighboring countries are going through a humanitarian crisis on a scale we have rarely seen," a senior UN humanitarian official told reporters Friday, fresh after visiting the war-torn country.

In a teleconference link from Beirut, Lebanon, to UN headquarters here, UN Undersecretary-General Valerie Amos, also head of the UN Office for the Coordination of Humanitarian Affairs (OCHA), said she left the Syrian capital of Damascus Friday.

"I held talks with members of the government and humanitarian partners about improving our aid operations," she said, praising the 4,500 UN staff in Syria, "working with non-governmental organizations (NGOs) and community organizations to get help to the people who need it most, in government- and opposition- controlled areas."

Describing the sessions as "positive meetings," Amos expressed the hope "we will make progress in addressing some of the administrative problems we have faced in getting approval for field operations, convoys and visas for humanitarian aid workers."

"The fighting is having a terrible impact on ordinary people; neighborhoods have been shelled indiscriminately and entire towns have been besieged," she said.

Also on Friday, UN Secretary-General Ban Ki-moon, addressing a Syrian humanitarian initiative session on the sidelines of the G20 summit in St. Petersburg, Russia, described the situation as "a humanitarian crisis of unprecedented proportions in recent history. " G20 stands for the Group of 20 largest economies in the world.

"Conditions remain difficult in terms of security," he said. " Mortar attacks in Damascus alone are frequent and close."

"The humanitarian response is also hampered by a lack of funding," Ban said. "The (UN) World Food Program has already been forced to reduce the size of its food parcels to keep pace with the growing numbers in need. If additional isn't urgently received, there will be a break in the food pipeline in October."

Additionally, the secretary-general said the refugee appeal for neighboring countries was "severely underfunded," increasing the burden for hosting the refugees.

There is a three-billion-U.S. dollar request for the Regional Refugee Response Plan, only 37 percent of which has been funded, OCHA said, and 1.4 billion U.S. dollars have been requested for humanitarian assistance inside Syria with only 43 percent funded.

Amos repeated the grim Syrian statistics: more than 100,000 people killed; more than four million people have been displaced internally; two million people have fled Syria into neighboring countries as refugees and more than one-third of the people of Syria are in urgent need of humanitarian aid.

However, she quickly pointed out, "the crisis is affecting everyone (in Syria) with the depreciation of the currency and the destruction of essential infrastructure including health facilities."

Beyond Syria's borders, in neighboring countries, "the refugee crisis is having a very damaging effect on the economy, on the social structure and on host communities," while in Syria protecting civilians is paramount, said the undersecretary-general.

"The rise in the level of sectarian and sexual violence and ongoing human rights abuses are a major concern," she said.

Despite the very difficult and dangerous conditions, she said, "I was very proud of the commitment shown by the staff of the United Nations, by the volunteers of the Syrian Arab Red Crescent and the staff of other humanitarian organizations when I had the opportunity to speak with them yesterday (Thursday)."