Mr Gandhi's reaction came two days after results for assembly elections in Tripura, Meghalaya and Nagaland were declared on Saturday. The Congress lost Meghalaya and failed to score a single seat in Tripura and Nagaland.
The party won 21 seats in Meghalaya, where it was in power, and could not garner the support of regional outfits to cobble together a coalition government.
Top party leaders Ahmed Patel and Kamal Nath rushed to Shillong to talk to regional parties but to no avail.
"The Congress party respects the mandate of the people of Tripura, Nagaland and Meghalaya.
"We are committed to strengthening our party across the North East and to winning back the trust of the people. My sincere thanks to each and every Congress worker who toiled for the party," Mr Gandhi said on Twitter.
The Congress president had announced on Thursday that he would visit his 93-year-old grandmother in Italy over the Holi weekend.
Top party leaders had refrained from making any comment on the results.