The U.N. humanitarian chief says fighting between Syrian troops and rebels in the country's largest city, Aleppo, has forced 200,000 people to flee the area over the past two days.

Valerie Amos said in a statement Sunday the fighting is making it hard for humanitarian agencies to provide displaced residents with urgently needed food, mattresses, blankets, hygiene supplies and drinking water.

Also Sunday, Jordan opened its first official tent camp for refugees from neighboring Syria. Foreign Minister Nasser Judah said Jordan has taken in 142,000 Syrians, with up to 2,000 more arriving each day.

Turkey has been sheltering more than 44,000 Syrians.

Syrian activists said security forces fired tank shells and artillery against rebel positions in Aleppo Sunday.

The rebels held on to areas they captured in recent days, including the southwest district of Salaheddine. However, Syrian state media said troops ousted rebels from Salaheddine. There was no independent confirmation of either claim.

Syrian Foreign Minister Walid al-Moallem vowed the rebels in Aleppo will be defeated. He made the comment on a visit to Iran, Syria's strongest regional ally.

At a joint news conference with Moallem, Iranian Foreign Minister Ali Akbar Salehi dismissed any hopes of a peaceful transition in a post-Assad Syria, calling them an “illusion.”