Zimbabwean President Emmerson Mnangagwa has broken off a trip to Europe after violent protests in his home country.
Mr Mnangagwa had been due to attend the Davos economic summit where he was expected to seek investment for Zimbabwe.
Ministers say the opposition Movement for Democratic Change (MDC) is using sharp fuel price increases as a pretext for violence.
But the MDC accuses the authorities of a brutal crackdown.
How did the protests start?
Mr Mnangagwa announced a steep increase in the fuel price earlier this month.
The price rises were meant to tackle fuel shortages, but mean that Zimbabwe now has the most expensive fuel in the world, according to GlobalPetrolPrices.com.
Many Zimbabweans, worn down by years of economic hardship, have suddenly found they cannot even afford the bus fare to work.
This has led to angry protests in the capital, Harare, and the south-western city of Bulawayo.
How violent were the protests?
The Zimbabwe Human Rights NGO forum says at least 12 people were killed and 78 treated for gunshot injuries.
The rights group also says that over 240 people have been treated after being assaulted or tortured, while the opposition says government forces have attacked people in their homes.
The UN has called on the government to halt the “excessive use of force” by security forces, amid reports of door-to-door searches and the use of live ammunition.
The government blocked Facebook, Twitter and WhatsApp messaging apps last week, until a high court ordered it to restore access.
Mr Mnangagwa, who arrived back in Harare late on Monday night, condemned the demonstrations, saying “everyone has the right to protest, but this was not a peaceful protest”.
He accused protesters of “wanton violence and cynical destruction” and “looting police stations, stealing guns and uniforms”.