Turkish airstrikes hit several towns across northern Syria, including the city of Kobane late on Saturday, Kurdish-led forces and a Britain-based monitoring group have said.

The attacks come days after Ankara blamed the Kurdistan Workers’ party (PKK) for last Sunday’s deadly bombing in central Istanbul.

“Kobane, the city that defeated Isis, is subjected to bombardment by the aircraft of the Turkish occupation,” tweeted Farhad Shami, a spokesperson for the Kurdish-led Syrian Democratic Forces (SDF).

Turkey considers the Kurdish People’s Protection Units (YPG) – the main component of the SDF – an extension of the outlawed PKK.

Shami said there had also been airstrikes against two densely populated villages in the northern province of Aleppo and the north-eastern province of Hasakeh.

The UK-based Syrian Observatory for Human Rights reported that the Turkish military had carried out more than 20 airstrikes across the two provinces. The group has an extensive network of contacts across Syria.

Kobane, a Kurdish-majority town in northern Syria near the Turkish border, was captured by the Islamic State group in late 2014, though Kurdish fighters drove them out early the following year.

Both the PKK and the YPG have denied any involvement in the Istanbul attack, in which six people were killed.