A Turkish court has ruled that six Kurdish politicians who won seats in a parliamentary election this month must remain in prison to face terrorism charges.

The six politicians were elected as independents backed by the pro-Kurdish Peace and Democracy Party in the June 12 vote. Turkish authorities accuse them of having links to the Kurdistan Workers' Party, or PKK, designated as a terrorist group by Ankara.

The court in the southeastern city of Diyarbakir rejected appeals for the release of the six politicians in separate rulings on Saturday and Sunday. It said their continued detention is necessary to prevent them fleeing, destroying evidence or putting unlawful pressure on witnesses in the case.

One of the six politicians, Hatip Dicle, already had his parliamentary seat revoked by Turkey's electoral board due to a prior conviction for spreading terrorist propaganda. He was among 36 pro-Kurdish politicians who won seats in the election to the 550-seat assembly.

The Kurdish bloc has threatened to boycott the new parliament's first session on Tuesday to protest the ruling that stripped Dicle of his seat.

Turkey's ruling Justice and Development Party comfortably won a third term in the election, but fell short of the two-thirds majority it wanted to rewrite the constitution.

In recent days, Turkish judges also have refused to release three detained opposition politicians who were elected to the assembly. The three politicians all have been accused of participating in a plot to overthrow the Islamist-rooted Turkish government.