"My best wishes to the people of Telangana on the occasion of their Statehood Day. My best wishes for the state's development journey," he said.
"Greetings & good wishes to my sisters & brothers of Andhra Pradesh in the development journey of this hardworking state," Modi said in tweets.
Telangana, the 29th state of India, was carved out of Andhra Pradesh on this day last year, triggering protests in the Seemandhra region.
"On their Republic Day, my warm greetings & felicitations to the people of Italy," he tweeted.