“Yanukovych is declared internationally wanted, we set a special group to enter this case,” Xinhua quoted Makhnytsky as saying in a media briefing.
The international search has also been launched to find the former Interior Minister Vitaly Zakharchenko, Makhnytsky told reporters.
The country’s first Deputy Prosecutor General Mykola Golomsha, who also attended the briefing, said Yanukovych and Zakharchenko may still reside in Ukraine.
Earlier in the day, the general prosecutor’s office said Yanukovych, Zakharchenko and their close allies were being investigated on suspicion of wilful murder during the anti-government rallies, which left more than 80 people dead.
In Ukraine, those convicted of wilful murder could face detention for up to 15 years or a life sentence.
On Saturday, Ukrainian parliament passed a resolution to dismiss Yanukovych from his post and set an early election for May 25.
The whereabouts of Yanukovych are still unknown after he reportedly left the capital city late Friday to take part in a regional meeting in Kharkov city in east Ukraine.
According to media reports, the ousted president may be residing in the Crimean peninsula in southern Ukraine or has left the country.