The search party, which included 30 rescuers and 10 gendarmes, had to face freezing temperatures and strong winds, of over 150 kilometers per hour, rescue mountaineer George Cotunghiu said.
Several rescuers were caught up in two avalanches while searching for the tourists, but the team managed to pull them out unharmed.
Rescuers will fan out tomorrow morning in a renewed attempt to find the missing tourists.
However, chances are the two tourists were not able to survive two nights of temperatures as low as minus 20 Celsius degrees, rescuers said.
The tourists, a man and a woman, on Saturday contacted the mountain rescue services by cell phone to say they were trapped in Caraiman Valley on Bucegi mountain.
There are no reports of further contact between rescuers and the missing tourists.