Slovakia's Interior Minister Robert Kalinak has resigned amid a political scandal caused by the murder of a journalist and his fiancée.

Mr Kalinak bowed to pressure from a junior coalition partner and quit his posts, stripping Prime Minister Robert Fico of a key ally.

"It's important for stability to be maintained," Mr Kalinak told reporters as he announced his plan to step down.

His is the third resignation in a matter of weeks.

Mr Kalinak's decision follows anti-government protests in Bratislava on Friday.