A car bomb exploded on Monday outside the provincial HQ of the ruling Justice and Development Party (AKP) in the eastern Turkish city of Van, wounding at least 50 people, including four police, local authorities said.

Turkish officials blamed the outlawed Kurdistan Workers’ Party (PKK), which has waged a three-decade insurgency against the Turkish state and is considered a terrorist group by Ankara and its Western allies.

The attack took place near a police checkpoint outside the building, located in the heart of the city, the local governor’s office said in a statement.

A car "was blown up by members of the separatist terror organisation", it added, using a term to describe Kurdish militants.

Forty-six civilians and four police officers were injured, the state-run Anadolu news agency reported.

CNN-Turk television reported that some Iranian tourists in the bustling city were among the injured.

There was no immediate claim of responsibility for the bombing, which came on the first day of the Muslim holiday of Eid Al-Adha.

But Besir Atalay, an AKP lawmaker from Van, pointed the finger of blame at the PKK.

"The terrorist organisation has targeted our party building and the AKP’s presence in the past. This is one of their attacks," he added, in live comments on the private NTV television.

Witnesses said the blast shattered windows in the vicinity and the AKP’s provincial offices sustained severe damage.

Several ambulances rushed to the scene and television images showed water cannon being used to douse a fire.

Van, a city with a mixed Kurdish and Turkish population on the shores of the lake of the same name, has generally been spared the worst of attacks like those seen in the nearby city of Diyarbakir.

The city is a popular tourist destination, particularly with Iranians who arrive from across the border in huge numbers to enjoy shopping and the relaxed atmosphere.

The US embassy in Ankara condemned what it called a "terrorist attack", adding that such criminal acts were never justified.

"The fact that the terrorists struck on the first day of the Sacrifice Holiday is particularly disgraceful," the embassy said in a statement posted on its official Twitter account.

The blast came a day after the government announced the removal of 28 mayors, mainly over alleged links to the PKK in a move strongly denounced by pro-Kurdish parties.

President Recep Tayyip Erdogan defended the suspension of the mayors, saying it was a long-overdue move.