Iraq's top Shi'ite Muslim cleric has expressed concern about thesecurity pact approved earlier this week allowing U.S. troops to remainin the country for three more years.

A senior aide to GrandAyatollah Ali al-Sistani said Saturday that the influential clericfears the deal will not guarantee Iraq's sovereignty. He also said hefeels there is no national consensus on it.

Top Shi'ite Cleric Expresses Concern about Iraq-US Security Pact

The aide saidAyatollah al-Sistani supports holding a referendum on the pact, whichlawmakers agreed to do in order to get the approval of the main Sunnifaction.

Top Shi'ite Cleric Expresses Concern about Iraq-US Security Pact

The reclusive cleric does not often get directlyinvolved in politics, but his views carry immense weight in Iraq'slarge Shi'ite community.

Top Shi'ite Cleric Expresses Concern about Iraq-US Security Pact

Iraqi lawmakers signed the securitypact with the United States earlier this week. It was approved by themain Sunni, Shi'ite and Kurdish factions, but opposed by lawmakersloyal to opposition cleric Moqtada al-Sadr.

The deal is expectedto be approved by Iraq's three-member presidential council. Theagreement would replace the U.N. mandate for the U.S. military presencein Iraq. That mandate expires December 31.

The new securityagreement calls for U.S. forces to withdraw from Iraqi cities by June30, 2009, as an interim step. It also gives Iraq strict oversight oversome 150,000 U.S. forces in the country.

Earlier Saturday, arocket attack near a U.N. compound in Baghdad's heavily fortified GreenZone killed at least two foreign workers and wounded at least 15 others.

AU.N. statement said the two foreigners killed were working for acatering company. The victims' nationalities were not immediatelyreported.

The United Nations has had a limited presence in Iraqsince a suicide bomber struck the organization's Baghdad headquartersfive years ago. The blast killed 22 people, including top U.N. envoySergio Viera de Mello.