British and Australian forces handed over security responsibility for relatively peaceful Muthanna province to Iraqi forces on Thursday in the first such transfer of an entire province.
Prime Minister Nouri al-Maliki hailed the security transfer as an important step toward the goal of full Iraqi responsibility for all 18 provinces by the end of next year.
But at least 19 people were killed in attacks nationwide, illustrating the security challenge faced by this country.
"It is a great national day that will be registered in the history of Iraq. This step will bring happiness to all Iraqis," al-Maliki said during a handover ceremony in the provincial capital of Samawah. "Be sure that the terrorists want to destroy and foil the process of taking over the security issue and to hamper the political process and the national unity government."