A Turkish soldier whose brother was killed in an attack by Kurdistan Workers Party (PKK) militants launched a stinging attack Sunday on the government's "anti-terror" campaign at his funeral.

Ali Alkan, a captain in the Turkish army, was killed Saturday in southeastern Sirnak province in an attack blamed on PKK rebels who have ripped up a 2013 ceasefire as the government presses a large-scale military operation.

His funeral in his home region of Osmaniye in southern Turkey was marked by immediate tensions, with thousands shouting slogans against the ruling Justice and Development Party (AKP) of President Recep Tayyip Erdogan.

But in extraordinary scenes, his elder brother Mehmet, a lieutenant colonel and dressed in full military uniform, embraced the coffin and launched into a tearful tirade against the government.

"Who has killed him? Who is the reason for this?" Mehmet Alkan yelled tearfully, casting away his military cap, according to footage broadcast by the Cihan news agency.

"It's those who said there would be a solution who now only talk of war."

Erdogan pursued a so-called "solution process" to make peace with Kurdish rebels but is now vowing to press the offensive until the last militant is killed.

As the coffin was led away, Mehmet Alkan lashed out at the government over comments last week by Energy Minister Taner Yildiz that he too would like to be a martyr.

"There is really nothing like sitting around in a palace with 30 bodyguards and going about in an armoured car and saying 'I want to be martyr'," he said with heavy sarcasm.

"Just get out and go there," he added bitterly.

The footage -- which has been widely shared on social media in Turkey -- is a huge embarrassment to the government which has tried to honour the fallen soldiers as "martyrs" who died a glorious death.

The reports on state media did not mention the incident, saying only that Ali Alkan had been laid to rest.

Funerals of soldiers killed by the PKK, particularly ceremonies in Ankara, have been tightly controlled events attended by top officials and often broadcast live on television.

However there is growing concern over the extent of the military death toll, with over 50 Turkish soldiers and police killed in the last month.

Health Minister Mehmet Muezzinoglu and Deputy Prime Minister Yalcin Akdogan were both heckled when they attended funerals last week.

The region of Osmaniye -- a stronghold of the Nationalist Movement Party (MHP) and with strong connections to the Turkish military -- has lost 6 soldiers in the last 20 days alone, according to Turkish media reports.