Australians trapped in besieged South Sudan city A man from a Dinka tribe holds his AK 47 rifle in front of cows in a Dinka cattle herders camp near Rumbek, central South Sudan. Nairobi: Australians, British, Canadian and Kenyan citizens are among 3000 foreigners trapped in a South Sudan city experiencing bouts of heavy machine gun fire, one of the most violent areas of a weeklong conflict that has likely killed more than 1000 people, a top UN official says. Ugandans and Ethiopians are also among 17,000 people seeking protection at a UN base in Bor, a city that could see increased violence in coming days, said Toby Lanzer, the UN's humanitarian co-ordinator. The death toll from a week of violence in South Sudan has likely surpassed 1000 people, though there are no firm numbers available, he said. The number of internal refugees is probably more than 100,000, said Lanzer, who is seeking urgent financial assistance from the US, Britain and other European countries. United Nations' non-critical staff boarding a United Nations plane to be taken away from Juba. "I know there are many thousands of people seeking protection in churches," Lanzer said. I know that we have our own staff that have literally walked into the bush and are communicating from there. That's where they say they are safest. Bor is the city where rebel forces fired on three US military aircraft on Saturday, forcing the Ospreys - advanced helicopter-aeroplane hybrids - to abort their evacuation mission. On Sunday the US evacuated Americans by civilian US and UN helicopters. The US over the past week has evacuated 380 Americans and 300 others from South Sudan, which has seen vicious, ethnically targeted violence. Lanzer, who spent the weekend in Bor, said the city is experiencing tense, sporadic clashes and "fairly consistent gunfire and heavy machine gunfire." The army is "now ready to move to Bor," President Salva Kiir told parliament, adding that the counter-attack to wrest back the town after it was captured on Wednesday was delayed until the US had airlifted citizens out. The comments came despite days of shuttle diplomacy by African nations and calls from the US, Britain and the United Nations for the fighting to stop. The US special envoy to South Sudan, Donald Booth, arrived in the troubled capital of Juba on Monday.