Unidentified assailants have killed at least six Palestinians in Baghdad, prompting more than 200 Palestinians to flee from the city to the Syria-Iraq border where they are now stranded, the UN refugee agency said Friday. The UN High Commissioner for Refugees said the killings occurred over the past two weeks, citing reports from its staff in Baghdad. The agency said it has been trying to negotiate entry into Syria for the group - which includes pregnant women and children. Damascus allowed 287 Palestinians to enter last month after they were refused entry to Jordan. But Syria has said no newcomers will be accepted, UNHCR spokesman Ron Redmond said.