Singh called up states's Health Minister Hemanta Biswa Sarma to enquire about the condition in the state, a PMO statement said.
The Prime Minister assured the Assam government of all help to deal with the flood situation there, it said.
The statement said Singh also spoke to Defence Minister A K Antony "urging full army assistance for the rescue and relief operations in the affected areas".
The situation deteriorated in the state today as 23 of the 27 districts came in the grip of floods in which 26 people have died.
