A video showing an aide to Turkey's prime minister kicking a protester held on the ground by special forces police has sparked outrage, tarnishing the Turkish leader's image ahead of his expected run for president.
Turkish newspapers also published photographs showing the adviser kicking the protester and identified him as Yusuf Yerkel, a deputy chief of staff at Prime Minister Recep Tayyip Erdogan's office and adviser to the prime minister.
The incident occurred during Erdogan's visit to a coal mine in the western town of Soma where at least 283 miners were killed in Turkey's worst mining disaster. Scores of others are still missing.
Angry protesters heckled Erdogan and scuffles broke out between demonstrators and police in Soma, forcing the Turkish leader to take refuge in a supermarket before being driven off in a black vehicle.
Hurriyet newspaper said a protester kicked a vehicle in Erdogan's convoy, prompting the special forces police to jump in and force the man to the ground. Yerkel then kicked the protester "three or four times," the paper said.
Yerkel has issued a statement that expressed regret but also claimed that he was provoked.
"I am sorry that I was not able to keep calm despite all the provocations, insults and attacks that I was subjected to," he said.
Twitter was abuzz with posts condemning Yerkel's action and an opposition party demanded an explanation for it.
"Do his responsibilities include beating up and kicking protesters or citizens? On which legal grounds was he given this authority?" lawmaker Ugur Bayraktutan asked in a question submitted for the government to answer.
The prime minister's office distanced itself from the incident, with one official saying the issue was Yerkel's "own personal matter." The official was not allowed to give his name to the press without authorisation, which he did not have.
Erdogan is widely expected to run in Turkey's presidential election in August, although he has not yet announced his candidacy. He has already served the maximum three terms as prime minister.