(AKI) -- Iraq's most influential Shiite cleric, Ali al Sistani, has come out against the incorporation of the northern city of Kirkuk, one of Iraq's riches oil producing centres, into an autonomous Kuridsh state. "His Excellency [al Sistani] will not allow Kirkuk to be included in Kurdistan since it belongs to all Iraqis regardless of their national, religious and confessional background", said the Iraq news agency, quoting a press release from Sistani's office.

"We have to avoid the squandering of the country's wealth among people who give themselves the right to speak on behalf of Iraq, trying to split the resources according to their personal interests, regardless from where they come from - South or North", the release went on saying.

The issue of federalism, which has been espoused by Kurds to grant their Kurdistan region autonomy, is one of the main sticking points delaying the drafting of a new constitution, which needs to be presented to the National Assembly parliament.

Kurdish leaders are adamant that Kirkuk - a traditionally Kurdish city which went through a process Arabisation during the rule of Saddam Hussein - be included in their territory and have called for a referendum.

Shiites and sunnites, who respectively make up for 63 and 35 percent of Iraq's population, feel threatened by federalism as they fear they might lose to the Kurds the oil rich Kurdistan.