Lieutenant-Colonel Kadhim Abbas and the region's deputy governor said the two men worked at a detergent plant inside an industrial complex surrounding Baiji's oil refinery, the biggest in Iraq.
At least six armed men, in two unmarked cars, grabbed the two German engineers, Abbas said.
AFP reports that one person was killed and four others were wounded in a series of bombings on Tuesday, just hours before the resumption of the trial of Saddam Hussein, the deposed Iraqi leader, security officials said.
In one of these incidents, a bomb exploded near al-Tahrir Square in Baghdad's Wahda neighbourhood at about 8.30am, AP said quoting police Major Qusai Ibrahim.
Also on Tuesday, 20 high school students were wounded, two seriously, when a roadside bomb targeting a British army patrol exploded in the southern Iraqi city of Basra, a British military official said.
Two US soldiers were killed on Monday when their vehicle was struck by a roadside bomb in southeast Baghdad and two marines died in a vehicle accident in western Iraq, the US military said.
One of the soldiers was killed at the scene while the other died on his way to a hospital.
A roadside bomb in Kirkuk aimed
at US soldiers killed a pedestrian
The marines died in a non-hostile vehicle accident near al-Taqaddum, about 70km west of Baghdad.
Tuesday's bombing in Basra occurred as students were leaving school after writing their mid-term exams.
Brigadier Patrick Marriot told Reuters the target of the roadside bomb had been a British army patrol. A British military spokesman said one soldier suffered minor injuries.
Elsewhere, US marines and Iraqi soldiers conducted a ninth day of sweeping operations through fields and villages along the western Euphrates River valley on Tuesday, in an attempt to isolate fighters and confiscate weapons and ammunition, the US military said.
Operation Wadi Aljundi (Koa Canyon) in the troubled western province of Anbar has yielded thousands of pieces of ordnance, the US military said, but there was no word on any arrests.
The bodies of eight police recruits were found near Dujail on Monday; the eight were among 42 abducted after being ambushed in a violence-prone area north of Baghdad, police said.
The Iraqi army said it raided areas around the city of Baquba, 65km north of Baghdad, arresting 19 wanted men and seizing a number of weapons, ammunition and explosives.
Armed men killed an official with the Kurdistan Democratic Party as he was driving to work on Monday, east of Mosul, 360km northwest of Baghdad, Abd al-Ghani Yahya, a party spokesman, said on Tuesday.
Policemen remove the bodies of
victims of a bombing on Monday
In the northern town of Kirkuk, a pedestrian was killed and four other people wounded when a roadside bomb exploded near a US patrol, police said. US soldiers were uninjured, they added.
A car bomb also exploded in the northern city of Mosul, but there were no casualties.
In Baghdad, a rubbish collector was injured by the explosion of a bomb hidden in rubbish in the centre of town.
A leading Sunni Arab party on Tuesday called on fellow Sunnis to confront armed attacks on their community "by any suitable means" in the wake of a raid on a Sunni neighbourhood in Baghdad in which three men were killed and more than 20 abducted.
The call for Sunnis to defend themselves was made in a statement issued by the Iraqi Islamic Party a day after armed men, some wearing uniforms of the Shia-led security forces, swept into the Tubji area of Baghdad, raiding houses, abducting males and shooting three men to death.
Iraqi Islamic Party leaders want
Sunnis to defend themselves
An Interior Ministry official denied police involvement, saying an investigation is under way and the armed men may have been disguised as commandos.
In Samarra, 95km north of Baghdad, Sunni leaders have called for a three-day strike to condemn the killings of at least 31 Sunnis who were kidnapped from their bus last week after being rejected entry into the police academy.
Their bodies were found in farmland near the city of Dujail, north of Baghdad, after a squad of armed men stopped their bus on a country back road before executing them.
At least four of the men remain unaccounted for. It was unclear who was behind the kidnappings and killings of the failed police recruits.
Late on Monday, a senior official of a government organisation that administers Sunni mosques was slain by armed men as he drove home from evening prayers at a Baghdad mosque.
Naji Muhammad al-Ithaw, 55, had served as a spokesman for the Sunni Endowments and was a regular contributor to Baghdad newspapers.