A number of aid agencies are reducing their operations in Iraq
The International Committee of the Red Cross is cutting back its operations in Iraq after warnings that it could be targeted for attack.
The number of foreign staff in Baghdad is being reduced to about 50 as the level of violence throughout the country has failed to abate and the organisation fears that US-led forces cannot ensure security.
"It's a very difficult decision. It's a heartbreaking decision for us to reduce our staff," Nada Doumani of the ICRC told the BBC.
"We believe these warnings are to be taken seriously... It's very depressing for the Iraqis to realise that after four months... they don't feel safe in their own country."
The Red Cross tends to stay put when everyone else goes, so its decision to reduce staff is likely to be followed by other agencies, the BBC's Susannah Price in Baghdad says.
Different organisations are reviewing their operations, following Tuesday's bombing of the United Nations compound in Baghdad, in which more than 20 people died.
Attacks against Iraqi civilians have also continued, with three killed and nine injured in an assassination attempt on leading Shia Muslim cleric Grand Ayatollah Seyed Mohammed Said al-Hakim in the Iraqi holy city of Najaf.
The cleric received only scratches in the blast at his office on Sunday afternoon but two of his bodyguards and a driver were killed.
The Red Cross has suffered its own losses with the death of two workers.
The organisation said it would be forced to cut services further if the threat to its staff remained.
The ICRC in Baghdad is involved in a number of key operations which include:
Supplying hospitals with medical equipment and drugs
Visiting those detained by the American forces
Helping families trace missing relatives
Supplying the only hospital in Baghdad for the mentally ill
The UN, which lost its top envoy Sergio Vieira de Mello in the Baghdad compound blast, has sent non-essential administrative staff out of the country.
In another development on Sunday, medical personnel working for Spain's Movement for Peace, Disarmament and Liberty returned from Iraq.
"Baghdad is a lawless city," said Doctor Gabriel Espana on arrival in Madrid.
The assassination attempt on Ayatollah al-Hakim took place when a device connected to a gas canister went off near his office after he had just returned from midday prayers.
A spokesman for the Supreme Council for the Islamic
Revolution in Iraq (Sciri) - a leading Shia Muslim organisation - said a strange man had been seen before the blast.
One Shia official, Mohsen al-Hakim, said the prime suspects for the attack were Saddam loyalists wishing to stir up trouble between Shia and Sunni Muslims.
Aid agencies affected
ICRC - reducing Baghdad staff
UN - non-essential admin staff leaving
Movement for Peace, Disarmament and Liberty - medics returned to Spain
However, Ayatollah al-Hakim was one of a group of three top Shia leaders issued death threats by a rival Shia cleric shortly after Saddam Hussein was toppled on 9 April.
Our correspondent says it seems likely the attack was linked to a power struggle within the Shia community.
Ayatollah al-Hakim is a leading member of the Hawza, the leading Shia seminary in Iraq.
The Hawza is led by Grand Ayatollah Ali Sistani, whom the US-led coalition praises for his moderate views.
But more hardline Shia groups have made their opposition to the coalition forces clear, our correspondent says.