UN-Arab League mediator Lakhdar Brahimi will visit Syria’s close ally Iran this weekend to try to break a deadlock in political talks aimed at ending Syria’s three-year war, Secretary-General Ban Ki-moon announced Friday.

Ban said the talks are “in crisis” because the Syrian government and opposition aren’t willing to compromise.

He told reporters that Iran as a major country in the region “can play an important role, including impressing upon the Syrian authorities to come to the Geneva conference in a more constructive way.”

Iran has supplied President Bashar Assad with cash, weapons and Shiite fighters linked to Hezbollah, and the secretary-general was forced to rescind his last-minute invitation to Tehran to attend the Jan. 23 opening of the last round of peace talks in Geneva, under pressure from the United States and the Syrian opposition.

Brahimi last visited Iran in late October and the UN said he will arrive in Tehran on Sunday.

In a parallel effort to break the political impasse, Ban also urged the United States and Russia, who initiated the Geneva talks, “to take clear steps to re-energize the political process.”

Brahimi made no mention of his visit to Iran in a closed speech to the General Assembly where he expressed fear that presidential elections in Syria “will slam the door to the Geneva negotiations for the foreseeable future.”

“I very much doubt that any of the opposition groups that are strongly opposed to the present government, inside or outside of the country, will consider that negotiations may continue if presidential elections are scheduled in May or June,” he said, according to a transcript released afterward.

Syria’s UN Ambassador Bashar Ja’afari told reporters in Arabic that a presidential election will be held in June or July, and called it “an internal affair.”

Assad’s seven-year term as president officially expires on July 17 but he has not announced whether he will seek re-election. On Thursday, Syria’s parliament unanimously approved a new election law allowing multiple candidates to run for president and parliament.

Brahimi said he doubts very much that another term for Assad “will put an end to the unbearable suffering of the Syrian people, stop the destruction of country, and re-establish harmony and mutual confidence in the region.”

Secretary-General Ban said there is “no alternative” to a political solution but if Assad becomes a candidate for president it will be “very difficult” to move ahead with the Geneva process.

At last month’s talks, Brahimi wanted both sides to hold parallel discussions on terrorism, which is a major concern for government, and the establishment of a transitional governing body for Syria agreed on by major powers at a Geneva conference in June 2012.

The opposition agreed, but Brahimi said the government insisted “that the issue of terrorism had to be discussed until some common ground on terrorism was achieved and agreed to by the opposition.” While the government said it was willing to discuss a transitional government, Brahimi said the opposition “was strongly suspicious” the government didn’t want a discussion “any time soon, if ever.”

Ja’afari, who was Syria’s chief negotiator at the talks, told reporters: “I need the other side to acknowledge the presence of terrorism in Syria before discussing with me the future of my own country.”

Ja’afari also rebuked Brahimi, implying that he was taking the side of the opposition. He said he advised Brahimi during the General Assembly session “to behave and to act neutrally, objectively, genuinely speaking without taking sides, without being biased.”

Brahimi painted a grim picture of the worsening “humanitarian catastrophe” in Syria, which he called “mind-boggling:” Close to 10 million people who need aid to survive; the number of refugees already passing two million and expected to reach four million by the end of the year if the conflict continues; and the number of deaths reaching 350,000, if not more, by 2015.

“These numbers sound frighteningly high,” Brahimi said. “But when one hears that half a million people left Aleppo during the past few weeks, we see that those levels will alas be attained.”

Calling the economic situation in Syria “catastrophic,” he warned that that Syria is “on the cusp of colossal destruction that could see it become a failed state by 2015.” He said GDP has contracted by 42 percent from pre-crisis levels and unemployment has reached 42 percent.

While the Syrian government is confident “that their side will win on the battlefield and soon,” Brahimi said the assessment of most observers is that neither side can win a military victory in 2014.

“Whether the process in Geneva resumes or not, whether the Syrian government holds a presidential election or not, the secretary-general for his part, and the United Nations as a whole, do not have the option of walking away from Syria,” he said. “And left alone, Syria will continue to burn and engulf with it the region.”

Copyright 2014 The Associated Press.