Gunmen on Wednesday threw a hand grenade at the office of Iraq's parliament deputy speaker, Shakhwan Abdullah, in the northern city of Kirkuk, a security official said.
The Iraqi News Agency said damage to the building was minimal and no casualties were reported.
Mr Abdullah, who is affiliated with the powerful Kurdistan Democratic Party, described the attack as a "terrorist and cowardly act".
He said the attack was a "desperate attempt to disturb stability and security in the city".
Iraqi security forces cordoned off the area and launched an investigation into the incident.
Mr Abdullah was appointed to the position nearly a week ago after Iraq's new parliament elected Sunni legislator Mohammed Al Halbousi as speaker.
Hakim Al Zamili, who ran for populist cleric Moqtada Al Sadr’s party, was elected as Mr Halbousi’s first deputy speaker. Mr Abdulla was voted in as a second deputy during the session.
The development was an important step towards establishing a new government three months after a national election.
Over the past few days, Baghdad experienced attacks against the offices of politicians, civilians, and security personnel, using firearms, explosive devices and hand grenades.
On Saturday a hand grenade was tossed into the office of Sunni politician Abdul-Karim Abtan Al Jubouri in Baghdad’s south-west neighbourhood of Sayyidiyah.
Last Friday, unknown gunmen attacked the Baghdad offices of two main Sunni parties. No injuries were reported in the attacks against the Taqadum party, led by Mr Al Halbousi, and the Azim coalition headed by tycoon Khamis Al Khanjar.
Security officials reported only minor damage.
Two people were hurt when two explosions rocked Baghdad late on Sunday, when the bombs simultaneously detonated at two branches of privately-owned banks in Baghdad’s Karrada neighbourhood.
The outcome of the country's early election showed the Sadrist bloc led by Mr Al Sadr as the biggest group with 73 seats, prompting an unsuccessful challenge to the election result by his Shiite rivals.
They include former prime minister Nouri Al Maliki, whose State of Law bloc won 33 seats, and the Iran-backed Fatah Alliance, which won 17 seats in the 329-member Iraqi Parliament.