The UN refugee agency has said it is increasingly concerned about the worsening situation of Palestinians living in the Iraqi capital, Bagdad.
More than 100 Palestinian families had received written death threats on Thursday and were concerned by the worsening situation, the agency said.
There is also concern about the health of 89 Palestinians who tried to flee Iraq but were refused entry to Jordan.
The refugees have spent a week stranded in the desert at the border crossing.
Jennifer Pagonis, a spokeswoman for the UN High Commissioner for Refugees, said the stranded group was "adamant they do not want to return any part of Iraq".
"They said the killings, disappearances, and hostage-taking affecting their families, neighbours and friends had become intolerable."
Ms Pagonis said the UNHCR was trying to deliver basic supplies to the group.
The Jordanian government closed the border on Sunday, fearful of an influx of Palestinian refugees.
The human rights group Amnesty International has said Jordan is obliged to allow the Palestinians over the border.
Ms Pagonis said the UNHCR had been told this week of further death threats sent to some Palestinian families.
It is not known who threatened the Palestinians, in the Hurriya district of Baghdad, but the messages accused them of collaborating with the "Nawasib", a derogatory term for radical Sunnis and followers of the former Iraqi president, Saddam Hussein.
"On Thursday, we heard from the Palestinian community in Baghdad that reportedly over 100 families had received written death threats and that many are in a state of shock and panic," Ms Pagonis said.
"This panic may spread and lead to more Palestinians fleeing Baghdad."
Many Palestinians have stopped going to work or sending their children to school because of fears over the worsening security situation, she said.
"While Iraqis are also affected by the general insecurity in Iraq, Palestinians feel especially vulnerable and targeted as they were perceived to have been treated favourably by the previous regime," she added.
The UNHCR estimates about 34,000 Palestinians currently live in Iraq.
Many arrived after the Arab-Israeli wars in 1948 and 1967 and enjoyed generous financial support from former Iraqi President Saddam Hussein, who championed the Palestinian cause.
The Palestinians' healthcare, school and housing was subsidised and many received government jobs, leading to resentment among many Iraqis.