Internet users in Turkey have been experiencing severe difficulties accessing social media after the country was plunged into new turbulence by the detention of its main pro-Kurdish leaders, a watchdog said.

The messaging service WhatsApp was not working, and users also reported severe problems accessing Twitter, Facebook, YouTube and other sites, Internet users said.

Prime Minister Binali Yildirm did not directly confirm that blocks were in place but acknowledged that "from time to time for security reasons we can use such measures".

"These are temporary measures. Once the danger is passed, everything returns to normal," he told reporters in Istanbul in televised comments.

The problems came after 11 MPs from the pro-Kurdish Peoples' Democratic Party (HDP), including its co-leaders Figen Yuksekdag and Selahattin Demirtas, were detained in an unprecedented crackdown. Shortly after the arrests of at least 12 legislators, as explosion hit Diyarbakir, the largest city in Turkey's mainly pro-Kurdish south-east region.