Turkey’s main Kurdish party accused the government Saturday of turning a blind eye to Islamic State militants on its soil, claiming that a suicide bomber crossed over the border into Syria before carrying out a deadly attack.

Four Islamic State militants reportedly blew themselves up in the Syrian border town of Kobane, one detonating a car bomb at the Mursitpinar border crossing. A second bomber detonated an explosive vest in the same area, before two more suicide attacks hit the southwestern edge of the town.

The Islamic State claimed three suicide attacks in Kobane’s border-crossing point, reported the SITE Intelligence Group, which tracks militant postings online.

The Britain-based Syrian Observatory for Human Rights and Idris Nassan, a Kurdish official in the town, said the vehicle used in the car bombing at dawn had come from Turkish territory.

HDP, Turkey’s pro-Kurdish party said the militants were using state grain depots on the Turkish side of the border as a base from which to attack Kobane. It also described the militants’ presence in an area patrolled by Turkish security forces as a “scandal.”

“As we have been pointing out for months, this once more proves that Islamic State is being supported” from inside Turkey, the HDP said in a statement.

A Turkish government statement Saturday confirmed that one of the suicide attacks involved a bomb-loaded vehicle that detonated on the Syrian side of the border. But it denied that the vehicle had crossed into Kobane through Turkey, which would be a first for the extremist fighters.

Turkish Prime Minister Ahmet Davutoglu’s office said in a statement that it was “definitely a lie” that the vehicle used in the bombing had crossed from Turkey. His office said Turkish security forces had taken “all necessary precautions” along the border.

Kurdish militias have been holding off Islamic State fighters for more than two months in Kobane. Neither side has gained a decisive advantage despite U.S.-led airstrikes meant to push back the Islamic State insurgents.

Turkey, while previously backing the Syrian rebels fighting to topple President Bashar al-Assad in that country’s civil war, has been hesitant to aid them in Kobane because it fears that could stoke Kurdish ambitions for an independent state.

That stance has infuriated Turkey’s Kurds, prompting violent protests in October in which about 40 people were killed.

— Reuters