United Nations Secretary-General Ban Ki-moon has warned that as fighting rages in Syria, sectarian hatred is on the rise, adding to pleas of aid groups for international action.

"The catalogue of war crimes is mounting. Sexual violence is widespread," said Ban speaking of the conflict in Syria in an address to a United States think tank in New York on Feb. 11.

Ban highlighted Syria as one of two major issues that threats huge, global consequences and he urged the international community to uphold its responsibilities in facing them. The second issue is climate.

"In both cases, the international community is not upholding its responsibilities," Ban told the Council on Foreign Relations while delivering the Sorensen Distinguished Lecture of that group, in an event moderated by CNN international news correspondent Christiane Amanpour.

"Both risk the harsh judgment of history should present trends continue. And both require collective action that must involve the United States," Ban said in the talk.

Ban announced plans to visit Washington D.C. later this week for talks with U.S. Secretary of State John Kerry and other government officials.

The three Western powers - Britain, France and the United States - on the U.N. Security Council and Russia and China are at an impasse over Syria and this has thwarted U.N. actions to alleviate the situation there.

"Syria is self-destructing," he said of the nearly two-year old conflict between the regime of President Bashar al-Assad and its opposition, which has left more than 60,000 people, mostly civilians, dead and more than four million people in need of humanitarian assistance.

"The situation cries out for action by the Security Council in particular," Ban said. "The Security Council must no longer stand on the sidelines, dead-locked, silently witnessing the slaughter. It must be willing, at long last, to come together and establish the parameters for the democratic transition that could save Syria."

The United Nations Children's Fund (UNICEF) said at the end of January that a fresh wave of 21,000 Syrians had arrived in Jordan's Za'atari refugee camp in the previous week alone.

The Geneva-based ACT Alliance called on the international community to commit the funds needed to address the mounting emergency, as the U.N. prepared to expand its humanitarian response to the crisis with some US$ 1.5 billion.

"The humanitarian crisis in Syria has reached desperate dimensions. The conflict has lasted 22 months. People are sleeping in the streets, unable to fulfill their basic needs, and there is a fear that the suffering will be exacerbated by the harsh winter and protracted conflict," said John Nduna, general secretary of ACT.

"Humanitarian aid should be rapidly scaled up with a massive increase of funding. Currently, the efforts remain severely underfunded," said Nduna, on the website of ACT an international emergency aid and development group founded by churches such as the World Council of Churches and the Lutheran World Federation.

In Syria, food, shelter, protection, medical support and education are urgently needed. Women and children constitute the majority of the affected population.

"The international community must not continue failing innocent civilians. In addition to a rapid increase of funds, humanitarian actors should commit to improve the effective coordination of the response. U.N.-led coordination is key to ensuring that pressing needs are met," Nduna urged.