Iraqi police say a suicide bomber has killed at least four people inside a police station in Diyala province.

They say at least 16 others were wounded in the attack in a market police station in Balad Ruz, northeast of Baghdad.

Meanwhile, radical Shi'ite cleric Moqtada al-Sadr condemned a U.S. plan to build a wall around a Sunni enclave surrounded by Shi'ite neighborhoods in Baghdad. He called the project sectarian and racist. Iraqi Prime Minister Nouri al-Maliki has criticized the plan.

In other news, Iran's Foreign Minister Manouchehr Mottaki says his country has not yet decided whether it will attend an international meeting on Iraq in Egypt next month.

The annoucement came after talks in Iran between Mottaki and his Iraqi counterpart, Hoshyar Zebari.

Earlier Wednesday, the U.S. military said it killed a top al-Qaida in Iraq terrorist in an operation in Al Anbar province last week. A statement identified him as Muhammad Abdullah Abbas al-Issawi, an al-Qaida security chief in the region.

In a separate statement, the military said coalition forces detained six terrorist suspects during operations in the northern city of Mosul and near the towns of Salman Pak and Karmah.

 Some information for this report was provided by AP and Reuters.