A crowd has attacked the headquarters of Turkey's pro-Kurdish HDP party, amid rising violence between Turkish forces and the militant Kurdish PKK group, BBC News reports.

Pictures from the scene appeared to show the HDP building in the capital, Ankara, on fire.

Earlier, Turkish ground forces crossed into Iraq in pursuit of Kurdish militants for the first time since a ceasefire with the PKK two years ago.

Turkish warplanes also launched a wave of air strikes on bases of the PKK (Kurdistan Workers' Party) in northern Iraq.

Nationalists staged rallies across Turkey on Tuesday, September 8 hours after 14 police officers were killed in a suspected PKK bomb attack on a minibus in the east of the country.

The bombing came a day after another militant attack on the Turkish military killed 16 soldiers.