Turkish officials say suspected Kurdish militants exchanged gunfire with police before detonating their vehicle in Turkey's Aegean coastal city of Izmir, killing a police officer and a courthouse employee.

Izmir Governor Erol Ayyildiz said two attackers who were killed by police following the blast were armed with Kalashnikov rifles and grenades when the car bomb exploded at a police checkpoint near a courthouse.

Earlier reports said a third attacker was on the run.

There was no immediate claim of responsibility, but Ayyildiz said preliminary signs indicated that the banned Kurdistan Workers Party (PKK) was behind it.

"The information so far suggests it is the PKK. Such a conclusion was reached after we assessed the attack and ID'd the people," Ayyildiz said.

Earlier reports said at least 10 others were wounded in the blast, while Ayyildiz put the number at "six or seven."

The PKK has carried out several attacks against Turkish security forces in the past year and a half. Islamic State (IS) militants have also staged numerous deadly attacks in the country.

Deputy Prime Minister Veysi Kaynak told reporters that weapons found at the scene suggested the assailants had planned a much larger assault.

"Based on the preparation, the weapons, the bombs and ammunition seized, it is understood that a big atrocity was being planned," he said.

The incident followed a shooting in Istanbul in which 39 people celebrating at a New Year's party were killed in an attack claimed by the Islamic State (IS) extremist group.

Earlier on January 5, police carried out raids in and around Istanbul and detained a number of people of Uyghur ethnicity over the massacre, state-run news agency Anadolu reported.

Kaynak said the gunman, who remains at large, was probably an ethnic Uyghur but he could not say for sure.

Kaynak also said Turkish authorities had established the gunman’s possible location and links.

Uyghurs are a mainly Muslim, Turkic-speaking minority in western China with significant diaspora communities across Central Asia and Turkey.

Turkey's foreign minister said on January 4 that authorities had identified the suspected gunman but did not provide further details.

With reporting by Reuters, AP, AFP, and dpa