China summoned Malaysia's ambassador on Wednesday to protest about the treatment of Chinese people there, state-run news agency Xinhua says.
The video has provoked outrage in Malaysia and China
The diplomatic action follows outrage over a video showing an ethnic Chinese woman being forced to perform naked squats in a Malaysian police station.
China has asked Malaysia to investigate immediately, Xinhua news agency said.
A Malaysian minister has apologised for saying foreigners who objected to police behaviour could leave Malaysia.
Noh Omar's apology was grudging at best, says the BBC's Jonathan Kent in Kuala Lumpur.
Mr Noh, the minister responsible for the police, said he was sorry if anyone had interpreted the comments negatively.
He had said: "If foreigners think that Malaysia police are brutal, please go back to their own countries and not to stay here.
"For me, it was conducted in accordance with the rules," he added.
On Wednesday, he said he had been misinterpreted.
"What I meant was Malaysia is a safe country. If foreigners think our police are cruel and the country is not safe, then they would have gone back home long time ago. I did not tell them to go back," he insisted.
But Prime Minister Abdullah Badawi took issue with his minister, who he said had been "reprimanded".
"Government officials should be more sensitive and careful when issuing
statements on the issue," Mr Abdullah said.
Calls for reform
Malaysian Ambassador to China Syed Norulzaman was summoned before Chinese Vice Foreign Minister Wu Dawei, who highlighted "the great importance to safeguarding the dignity and safety of Chinese citizens", according to Xinhua.
Mr Norulzaman said the Malaysian government and its people were shocked by the case, and that Malaysian Prime Minister Abdullah Ahmad Badawi had ordered an investigation, Xinhua said.
The case has also served to confirm many Malaysians' long-held suspicions about police brutality, our correspondent says.
There have been calls both for rapid reform and for Mr Noh's sacking.