A candidate for Iraq’s upcoming legislative elections was killed in the explosion of a car bomb in northern Baghdad, the capital’s security forces said Wednesday.

A bomb exploded after midnight under a vehicle belonging to Safaa al-Mashhadani, one of the candidates in next month’s parliamentary elections.

“The bomb resulted in his death and the injury of four others who were with him in the vehicle,” Baghdad Operations Command said in a statement.

Al-Mashhadani’s death marks the first political assassination ahead of Iraq’s elections, likely inflaming tensions in the highly polarized campaign and raising security concerns.

Iraq and decline in attacks

Iraq has seen a significant decline in such attacks in recent years, contributing to oil firms such as Exxon Mobil Corp. making a return to the country following a run of instability and conflict.

Al-Mashhadani was due to run on behalf of one of the country’s largest Sunni Muslim blocs.

The alliance, known as the Siyada Coalition, is led by prominent businessman Khamis al-Khanjar and includes several influential Sunni figures, such as the current parliamentary speaker Mahmoud al-Mashhadani.

No group has claimed responsibility for the attack, where four more people were injured.

Investigation ordered: PM

Both the parliament speaker and the prime minister said they have ordered an investigation into the assassination.

The incident took place in the Tarmiyah area, which is located some 40 kilometers (25 miles) north of the Iraqi capital, the speaker said. He describe the events as “a cowardly terrorist act”

“Tarmiyah has lost one of its righteous and loyal sons,” the speaker said. “He had an active presence in the political and social arena, defending the issues of his region and country with a sincere national spirit.”

Iraqis will head to the polls on Nov. 11 in the OPEC nation’s sixth parliamentary elections since the 2003 US-led invasion that toppled Saddam Hussein’s regime.