Iraqi officials say suicide bombings have killed at least 19 people in two attacks across northern Iraq.

In the deadliest strike Thursday, officials say a bomber blew himself up at a police recruiting center, killing 16 people and wounding 14 others. Police and hospital officials in the northwestern town of Sinjar say 14 of the dead are police recruits, and the other two are police officers.

Iraqi police officers inspect a crater as firefighters clean the road with water in the al-Ghabat area of central Mosul, Iraq, 29 May 2008

Hours earlier, officials say a suicide bomber driving a police vehicle struck a group of Iraqi security forces in Mosul. The attack killed at least three people, including two policemen, and wounded at least nine other people.

Separately, police say members of a U.S.-backed Iraqi neighborhood patrol killed at least 12 insurgents during a clash near the northern city of Tikrit. Police say the fighting erupted today when insurgents opened fire on the patrol.

Iraq's vice president, Adel Abdul-Mahdi, traveled to Tehran on Thursday, where he met with Iranian President Mahmoud Ahmedinajad and the newly-elected speaker of parliament, Ali Larijani, to discuss security issues. Iranian media say the men also discussed Tehran's concerns about a proposed U.S.-Iraqi security agreement, which would replace the current United Nations mandate for U.S. troops in Iraq.

In Mosul, U.S. forces captured 11 suspected al-Qaida militants. Major John Hall, a U.S. military spokesman, says one of the men is believed to be a senior al-Qaida in Iraq leader.

In other news, the families of five British men being held hostage in Iraq pleaded for their release in an interview with British radio (BBC).

The Britons were seized from an Iraqi Finance Ministry building in Baghdad one year ago.

Britain's ambassador to Iraq, Christopher Prentice, also issued a call for their release Friday to coincide with the anniversary of their kidnapping. He said the British government remains committed to working for the release of all hostages.

Some information for this report was provided by AP.