Jihadists took over Iraq's largest Christian town and surrounding areas on Thursday and sent tens of thousands of panicked residents fleeing towards autonomous Kurdistan, officials and witnesses said.

With a youthful and dynamic candidate, Turkey's main Kurdish political force is seeking to broaden its appeal in presidential polls where the votes of the Kurdish minority are set to play a crucial role.

Turkish Prime Minister Recep Tayyip Erdogan on Wednesday faced accusations of racism days before he stands in presidential elections after saying in a television interview that it was ugly to be called an Armenian.

During a live interview on the private NTV channel late Tuesday, Erdogan complained that the opposition was carrying out a smear campaign against him by claiming that he was from another ethnic origin.

Kurdish fighters from Iraq, Syria and Turkey joined forces in northern Iraq Wednesday in bid to reclaim areas lost to jihadists and rescue thousands of civilians stranded without food or water in nearby mountains.

The fate of the civilians, many of them from the Yazidi minority who fled to the Sinjar mountains after an attack by the Islamic State (IS) group at the weekend, has sparked international concern.

All 34 villages around Amerli are under jihadist control but the small Turkmen town is holding out, in one of the longest and most dramatic sieges of Iraq's current conflict.

Turkey's top election body on Tuesday banned a television advertisement by Prime Minister Recep Tayyip Erdogan in his campaign for president on the grounds that it contained excessive religious symbolism.

Erdogan, a pious Muslim who leads the Islamic-rooted Justice and Development Party (AKP), is the hot favorite to become the 12th president of modern Turkey in the August 10 elections and has unleashed an energetic campaign with TV adverts and billboards across the country.

The outlawed Kurdistan Workers' Party (PKK), which for years waged a deadly insurgency against Turkish authorities, called on all Kurdish armed groups Tuesday to unite against radical Islamist militants who have seized swathes of northern Iraq.

"Our efforts alone are not enough. There must be a joint (effort)" against the Islamic State (IS), the PKK's military leader Murat Karayilan said in remarks carried by the Radikal online newspaper.

Turkish authorities on Tuesday arrested dozens of police officers accused of illegally wire-tapping top officials including Prime Minister Recep Tayyip Erdogan, local media reported. 

Violent scuffles erupted on Monday in the Turkish parliament between opposition and ruling party lawmakers over the formation of a commission into the radical Islamist threat in neighboring Iraq.

Punches were thrown, suits grabbed and deputies pinned to the ground in the latest flare-up in the fractious parliament, days ahead of a presidential election where Prime Minister Recep Tayyip Erdogan will seek to move to become head of state.

Tens of thousands of supporters of Turkish Prime Minister Recep Tayyip Erdogan on Sunday massed in Istanbul for his last big rally in Turkey's largest city one week ahead of presidential elections.

Erdogan is widely expected to win the elections to become modern Turkey's twelfth president and staged a suitably presidential-style mass rally in the Istanbul suburb of Maltepe.