"Islamic State" (IS) militants are dangerously close to taking the Turkey-Syria border city of Kobani, seizing a secure compound on Friday according to the British-based Syrian Observatory for Human Rights. The compound included the headquarters of the local Kurdish administration and the city prison in Ayn al-Arab, more commonly called Kobani or Kobane by its majority Kurdish population.

According to the Observatory, the militants were also shelling the eastern side of the city, site of the border crossing with Turkey, trapping the civilians remaining in the city and preventing further refugees fleeing Kobani.

The jidhadists have successfully surrounded Kobani on three sides and fighting between IS and the Kurdish People's Protection Units (YPG) continues street by street, despite nine US air raids on Thursday night.

The outgunned YPG has criticized the Turkish government for preventing their forces from resupplying. In an unusual step from the generally neutral United Nations, the UN Envoy for Syria, Staffan de Mistura, has called for Ankara to allow Kurdish refugees to cross back across the border to help protect Kobani. He said that Turkey should "support the deterrent actions of the coalition through whatever means from their own territory," and at the very least allow volunteers and equipment across the border to assist in defending the city, according to news agency AFP.

Mistura issued grave warnings about what would befall the city if overtaken by IS as he urged Turkey to consider the up to 700 civilians still in the city and the 12,000 gathered nearby: "If this falls, the 700 plus perhaps if they move a little bit further the 12,000 people ... will be most likely massacred."

Nearly 500 people have died since attacks began near Kobani in the middle of September, and an estimated 300,000 have fled the surrounding region. Fierce fighting has been concentrated on the city itself since IS militants overran the city's defenses earlier this week.

If the jihadists take Kobani, they would control a large unbroken strip of the border with Turkey.

es/msh (AFP, dpa)