"We are urgently appealing to the Iraqi government and the multinational forces to provide protection and safety or an alternative safe location for this targeted group.
"We also ask the world to stop turning their back and provide a humane solution and safe haven to these people who have no way out."
Attacks and threats
The office of the UNHCR said that its discussions with the Iraqi authorities left "little room for optimism" that reliable protection could be afforded to the Palestinian refugees in the country.
The agency noted an increase in attacks and abductions of Palestinians living in Iraq. A previous mortar attack on Al-Baladiya injured 10 people, with several Palestinians kidnapped.
Leaflets carrying death threats have also been posted in Palestinian neighbourhoods of Baghdad.
The office said that the unsafe climate has forced "hundreds" to head to the border between Iraq and Syria.
Denied access by Syria, more than 350 Palestinians remain in "inhumane conditions" on the border.
UNHCR has appealed to Israel to allow admission into the occupied territories of Gaza and the West Bank.
No constructive response has been received from Israel.
The agency said that from resettlement countries, only Canada and Syria had taken Palestinians from Iraq in the past.