At least 199 people detained after twin bombings claimed by a Kurdish group left 44 people dead in Istanbul.

Police have arrested 199 people in raids across Turkey, targeting officials from the pro-Kurdish Peoples’ Democratic Party (HDP) over allegations of links to an outlawed Kurdish armed group, the state-run Anadolu agency said.

Monday’s operations were launched a day after the Kurdistan Freedom Hawks (TAK), an armed group believed to be a splinter of the Kurdistan Workers’ Party (PKK), claimed responsibility for twin bombings that killed 44 people and wounded 155 outside an Istanbul football stadium.

Hours after that claim, Turkish warplanes carried out air strikes against PKK targets in northern Iraq, destroying a base of the fighters and surrounding gun positions and shelters, an army statement said.

Around dawn, about 500 police officers, backed by armoured vehicles and a helicopter, launched an operation in the southern city of Adana and arrested 25 HDP officials, Anadolu said.

Counterterrorism police teams in Istanbul separately took into custody 20 HDP officials, including its provincial head, and carried out searches at various addresses including the party’s main offices in the city, the agency said.

The top HDP official in Ankara was among 17 people from the party held in raids in the capital, according to Anadolu, which added that 51 people were detained in the southern city of Mersin and five in the northwestern province of Manisa.

The leaders of the HDP, the second-largest opposition group in parliament, have already been jailed pending trial over alleged ties to the PKK, and Ankara regularly accuses the HDP of being an extension of the armed group.

The PKK is designated a “terrorist group” by Turkey, the United States and the European Union.

‘Fight terrorism to the end’

President Recep Tayyip Erdogan called a security meeting on Sunday after declaring at the funeral in Istanbul of five of the 30 police officers who were killed that Turkey would “fight terrorism to the end”.

Turkey was observing a day of mourning on Sunday, with flags flown at half-mast.

OPINION: Turkey’s war on the PKK

In June, TAK claimed responsibility for an attack that killed 11 people in Istanbul. Dozens of people were also killed by the group in the capital Ankara in February and March.

Turkey has been hit by a series of bombings this year and last, including five in Istanbul. Dozens of attacks blamed on the PKK and the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) groups took hundreds of lives.

The country is also still reeling from a failed July 15 coup blamed on the US-based preacher Fethullah Gulen which has been followed by a mass dismissal of his alleged supporters from state institutions.