By Michelle Nichols
UNITED NATIONS, Sept 4 (Reuters) - Syria's conflict has taken a brutal turn with other countries arming both sides, spreading misery and risking "unintended consequences as the fighting intensifies and spreads," U.N. chief Ban Ki-moon told the U.N. General Assembly on Tuesday.
The United Nations and Western officials have accused Iran of supplying weapons to Syria's pro-government forces, while Damascus has accused Qatar and Saudi Arabia of arming rebels determined to topple President Bashar al-Assad.
"This conflict has taken a particularly brutal turn," Ban said of the 17-month crisis. "The continuing militarization of the conflict is deeply tragic and highly dangerous."
"Those who provide arms to either side are only contributing to further misery - and the risk of unintended consequences as the fighting intensifies and spreads," he said.
A U.N. Security Council panel of independent experts that monitors sanctions against Iran has uncovered several examples of Iran transferring arms to Syria's government. The United States and Britain say they are providing non-lethal assistance to Syria's rebels such as communications equipment but not arms.
"The conflict is intensifying," Ban said. "The longer it goes on, the more difficult it will be to contain. The more difficult it will be to find a political solution. The more challenging it will be to rebuild the country and the economy."
The 193-nation General Assembly last month overwhelmingly approved a non-binding resolution, which expressed "grave concern" at the escalation of violence in Syria and condemned the U.N. Security Council for its failure to take strong action.
As Syria spirals deeper into civil war, the Security Council has been paralyzed on taking strong action as Russia and China have blocked three Western-backed resolutions that criticized Assad and threatened sanctions. A council meeting on Thursday on the crisis achieved nothing new.
"How many children will attend the funerals of their parents; how many parents will weep at the funerals of their children, before all parties agree to end the violence and destruction?" Ban said.
"The Syrian people have waited too long," he said. "And now the entire region is being engulfed by the complex dynamics of the conflict."
The new U.N.-Arab League mediator, Lakhdar Brahimi, who took up the role on Saturday and described his bid to broker peace as "nearly impossible," also briefly addressed the U.N. assembly.
"The death toll is staggering, the destruction is reaching catastrophic proportions and the suffering is immense," Brahimi said. "I am looking forward to my visit to Damascus in a few days time, and ... to all the countries who are in a position to help the Syrian-led political process become a reality."
Veteran Algerian diplomat Brahimi replaced Kofi Annan as the international mediator on the Syrian conflict. Annan had blamed the Security Council impasse for hampering his six-month bid to broker peace and leading to his decision to step down.
Syria's U.N. envoy Bashar Ja'afari said that Damascus was "open-minded and fully committed to the mission of Mr Brahimi in his endeavors to put an end to violence and find a Syrian-led political solution to the crisis."
"I'm calling on all member states, particularly those with direct influence .... on the parties rejecting political dialogue and the cessation of violence, I'm calling on them to follow in the footsteps of the government of Syria and seriously extend a helping hand to Mr Lakhdar Brahimi," Ja'afari said.
Ban described Brahimi's task as "daunting, but not insurmountable" and said that what was missing in international efforts to end the conflict was "a unity of effort that will have an impact on the ground."
Iran said last week it will form a team with other non-aligned countries to explore solutions to the crisis, while the United States has said it will turn to alternatives such as the "Friends of Syria" grouping of allied countries to pressure Assad after the Security Council's failure to act.
The United Nations says nearly 20,000 people have been killed in the conflict, which was sparked by a popular uprising against Assad.
Ban said the humanitarian situation was "grave and deteriorating" and the international aid response was constrained by a lack of funding. A $180 million international appeal was only half-funded, he said.
Assad pledged on Tuesday to allow the Red Cross to expand its humanitarian operations. The United Nations has said that more than 235,000 Syrian refugees have registered in Iraq, Jordan, Lebanon and Turkey, while about 1.2 million people have been displaced within Syria.
"The most pressing needs are water and sanitation, shelter, essential items such as blankets and hygiene kits, as well as emergency medial assistance," Ban said.
Turkey has repeatedly urged the United Nations to protect displaced Syrians inside their country, but creating a buffer zone for displaced Syrians would be difficult because a Security Council resolution would be needed to set up a no-fly zone, and Russia and China would not approve such a move, diplomats said.