A suicide bomber has targeted Iraqi army recruits in central Baghdad, killing 23 people and wounding 30, officials said, updating an earlier toll.

The interior ministry said the attack at a recruiting centre was carried out by a suicide bomber wearing an explosives belt.

The attack came a day after gunmen killed 12 soldiers and wounded four more at a military site in Al-Adhim, north of the capital.

Militants opposed to the Iraqi government frequently target security forces with bombings and shootings.

Violence in Iraq has reached a level not seen since 2008, when the country was just emerging from a brutal period of sectarian killings.

More than 300 people have died so far this month, already more than the overall toll for all of January 2013, according to figures based on security and medical sources.