Baghdad, Iraq (CNN) -- A suicide bomber wearing an explosives-packed vest attacked a police recruitment center in northern Iraq Tuesday, a bloody strike that killed at least 65 people and wounded 160 others.
The attacker -- who blew himself up when he was among hundreds of recruits -- staged the assault at a checkpoint where people usually wait their turn to enter the center.
The explosion caused a fire at a fuel station nearby, police in Tikrit said, and most of those killed and wounded were young men who came to join police forces.
Tikrit's general hospital was overwhelmed with wounded people, some of whom had to be sent to hospitals in nearby towns of the Salaheddin province and to other locations, such as Irbil and Kirkuk.
Salaheddin Deputy Governor Ameen Mohammed told Iraqiya state TV that security forces in the province are on full alert, and police said the local government announced a three-day mourning period in Salaheddin.
Iraqi Prime Nuri al-Maliki wants to get to the bottom of the incident, which he calls the latest of similar "heinous crimes."
He said it reflects "clear negligence and a shortcoming by the concerned authorities, so we will follow up this matter with all seriousness in order to determine those who are negligent, particularly those who are responsible of the recruitment cases and those who are behind today's painful tragedy."
Vice President Tariq Al-Hashimi deplored what he called a "cowardly" act.
"This new tragedy added to the tragedies of the unemployment of Iraqi youth," al-Hashimi said.
The vice president called on authorities to tackle unemployment and to keep young people from sinking into hunger and crime. He also said authorities need to reconsider how to protect recruits at such centers, which he called soft targets.
Mosques urged Tikrit residents to donate blood for the wounded.
The center is located nearly 100 miles north of Baghdad in Tikrit, the hometown of late Iraqi leader Saddam Hussein, and the facility is in one of Hussein's former palaces.
There has been no claim of responsibility but al Qaeda in Iraq, the Sunni Muslim-dominated militant group, has frequently claimed responsibility for such attacks. Tikrit is largely a Sunni Muslim city.
Iraqi recruitment centers have frequently been targeted in warfare over the years.
On August 17, 48 were killed when suicide bombers attacked a military recruitment center in the Bab al-Moudham commercial area of central Baghdad.
The same center was attacked again in September, and 12 people were killed.
The Islamic State of Iraq, an umbrella group for al Qaeda in Iraq and other Sunni extremist groups, claimed responsibility for that bombing, authorities said.
U.S. troops have ended their combat mission in Iraq and have focused on training and advising. But they feel the violence that occasionally erupts.
On Saturday, three U.S. soldiers were killed, two in northern Iraq and another in the central part of the country.
Under a U.S.-Iraqi security agreement, all U.S. troops are to leave Iraq by the end of the year. There are fewer than 50,000 American service members there now.
CNN's Jomana Karadsheh contributed to this report