Iraq's electoral commission says provincial elections due in October should be postponed because of parliament's delay in passing preparatory legislation.

The commission wrote to Iraqi lawmakers Sunday warning there is not enough time to hold provincial elections in October under international standards.

It urged parliament to quickly approve legislation on procedures for the elections to allow for a vote by the end of the year.

Washington hopes the provincial polls will give Iraq's Sunni Arab minority a greater say in local government. Iraqi Sunnis largely boycotted the last provincial elections in January 2005.

Meanwhile, Iraq's parliament speaker has welcomed the return of the main Iraqi Sunni political bloc to the country's Shi'ite-led government.

The Iraqi Accordance Front rejoined the Cabinet of Shi'ite Prime Minister Nouri al-Maliki Saturday after a year-long boycott.

Iraqi speaker Mahmoud al-Mashadani said Sunday the move gives the government a boost as it focuses on investment and reconstruction projects.

In violence on Sunday, Iraqi officials say U.S. forces shot and killed two relatives of the governor of northern Iraq's Salahuddin province. The U.S. military says its troops fired in self-defense at two armed men who were later determined to be related to the governor.

The military also says Iraqi forces killed six suspected militants during an operation in Baghdad.

Meanwhile, militants in Iraq who claim to have kidnapped five Britons released a video saying one of the hostages has committed suicide. British newspaper "The Sunday Times" says its office in Baghdad received the video.

British Prime Minister Gordon Brown said the video message is a very distressing development.

The hostages, a British computer expert and his four bodyguards, were abducted in May 2007 during a visit to an Iraqi finance ministry office.

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