In a setback to the opposition Congress in Karnataka ahead of 15 bye-polls in Karnataka, its senior leader and former lawmaker C.H. Vijayashankar from Mysuru returned to the ruling BJP in Bengaluru, a party official said on Tuesday.

"It was a home-coming for Vijayashankar who returned to the BJP two years after he quit in 2017 and joined the Congress in 2018 before the assembly elections," a party official told IANS.

Vijayashankar contested from the Mysuru Lok Sabha constituency in the 2019 general elections on a Congress ticket and lost to BJP's Pratap Simha.

Party's state unit president Naleen Kumar Kateel and state chief minister B.S. Yediyurappa were among the leaders and cadres who welcomed Vijayashankar back into the party fold.

"I have submitted my resignation from the Congress last week to its party high command and decided to rejoin the BJP for strengthening the party and its government in the state," Vijayashankar said on the occasion.

Vijayashankar's return to the saffron party comes ahead of the bye-elections in the southern state on December 5, including two in the old Mysuru region from where two former JD(S) rebel legislators A.H. Vishwanath and K.C. Narayana Gowda resigned from Hunsuru and K.R. Pet assembly segments, resulting in their disqualification and expulsion from the regional party in July.

"I was involved in party activities and held important positions when I was in the BJP until two years ago. In the Congress, however, no position or responsibilities were given to make best use of my services and political experiences. Hence, I have quit the party and came back to the BJP," Vijayashankar told reporters in Bengaluru.

Vijayashankar was BJP's district president and state unit's vice-president and represented twice the Hunsur assembly seat and the Lok Sabha twice from Mysuru in the past.

As the opposition leader in the assembly and former state chief minister Siddaramaiah, Vijayashankar is a popular Kurba leader in the state's southern region from the shepherd community.