EU 'extremely worried' over Turkey's arrest of Kurdish MPs

The European Union has expressed concern over Turkey's arrest of leaders and MPs from the country's main pro-Kurdish party, the bloc's foreign affairs head Federica Mogherini said on Friday.

EU relations with Turkey have been badly strained by the 'migrant crisis' but they took a sharp turn for the worse after President Recep Tayyip Erdogan embarked on a massive purge in the aftermath of a failed coup in July.

Mogherini, other top EU officials and many of the European Union's 28 member states have all repeatedly urged Erdogan not to breach human rights in the crackdown.

They have warned also that any re-introduction of the death penalty would immediately halt Turkey's already difficult accession talks as it pursues membership of the bloc.

Turkish police on Friday detained the two co-leaders of the country's main pro-Kurdish party, the Peoples' Democratic Party (HDP), as part of a major crackdown against the group.

Selahattin Demirtas was detained at his home in the southeastern city of Diyarbakir while the co-chairperson Figen Yuksekdag was detained in Ankara "within the framework of a terror investigation."

Their detention appeared part of a large-scale operation against the HDP, which is the third largest party in the Turkish parliament.

NTV television said the pair were accused of spreading propaganda for the outlawed Kurdistan Workers Party (PKK).

According to the Hurriyet daily, several other HDP MPs were also being detained including the prominent lawmaker Sirri Surreya Onder.

It listed the names of half a dozen other HDP lawmakers who had been detained so far in the operation.

Their detention followed a previous resolution by parliament allowing the immunity of MPs to be lifted.

The detentions come as Turkey remains under a state of emergency imposed in the wake of the July 15 failed coup, which critics say has gone well beyond targeting the actual coup plotters.

Mogherini's comments also come as hundreds were wounded after a large explosion hit Diyarbakir, the largest city in Turkey’s predominantly Kurdish southeast region on Friday.

Tensions have surged in the Kurdish-dominated southeast of Turkey since a fragile ceasefire declared by the PKK collapsed in 2015.

It has since stepped up its insurgency against the Turkish security forces, staging regular attacks that have claimed hundreds of lives among the military and the police.

The HDP seeks to promote the cause of Turkey's Kurdish minority and defend the rights of Kurds as well as those of women, gays and workers.

The charisma in particular of Demirtas – dubbed the "Kurdish Obama" by some admirers after the US president – earned it success at the ballot box.

It also divides all its top jobs between a man and a woman, as with the party chairmanship, which is shared between Demirtas and Yuksekdag.

But the authorities accuse the party of being a front for the PKK and failing to distance itself from terror, claims it has always vehemently denied.

Agencies contributed to this report