The decision to ban most food imports from the West shows that President Vladimir Putin has no intention of bowing to Western pressure over Ukraine.
Investors are beginning to favour the Eastern European country over South Africa as strike in mining and metals overshadow the seizure of Crimea.
Dozens of people have been killed as fighting broke out on the streets of Odessa, opening a new front in a conflict that has split the country.
US President Barack Obama has announced new sanctions in a bid to stop President Vladimir Putin from fomenting the rebellion in eastern Ukraine.
At least two people have been killed in a gunfight near a Ukrainian city, shaking an already fragile international accord to avert a wider conflict.
A day after an international deal in Geneva to defuse the East-West crisis in Ukraine, pro-Russian separatists vowed not to end their occupation.
