An al-Qaida-linked group in Iraq says it is holding 14 Iraqi soldiers and police and threatened to kill them within 72 hours unless the government releases Sunni Muslim prisoners.
The group also demanded the handover of those responsible for the rape of a Sunni woman known as Sabreen Janabi.
The al-Qaida group issued the threat in a statement posted on the Internet. The authenticity of the statement could not be verified.
Also Monday, a car bomber destroyed a span of a key bridge over the Diyala River, north of Baghdad. There were no casualties.
The attack came a day after three U.S. soldiers were killed when a suicide bomber destroyed part of highway overpass, south of Baghdad.
Meanwhile, Iraq's parliament voted to remove its Sunni speaker, Mahmoud al-Mashhadani, after a series of controversies involving the lawmaker. Mashhadani was involved in an incident Sunday in which his bodyguards allegedly assaulted a member of parliament.
In other news, U.N. Secretary-General Ban ki-Moon said in a report Monday he is willing to consider an expanded U.N. role and presence in Iraq, if adequate protection and security arrangements are put in place.
The United Nations reduced its staff in Iraq after the bombing of U.N. headquarters in Baghdad in 2003. The attack killed the special U.N. representative in Iraq, Sergio Vieira de Mello, among others.
Also, Britain's likely next prime minister, Finance Minister Gordon Brown, held talks Monday in Baghdad with Iraqi Prime Minister Nouri al-Maliki.
The British embassy said Brown was on a one-day trip to gather facts he will need to make informed decisions after he succeeds Tony Blair, which is widely expected.