"Our party's state President Dinesh Gundu Rao has directed our leaders, former ministers and legislators to boycott Yediyurappa's oath-taking ceremony as chief minister, as he has no moral right to assume power when his party does not have the majority in the Assembly," Congress spokesman Ravi Gowda told here.
Earlier in the day, Governor Vajubhai Vala invited Yediyurappa to take oath as chief minister at the Raj Bhavan at 6 p.m. and after the latter staked claim to form the BJP government in the state.
"I refuse to participate in this unholy event and instruct all #INCKarnataka leaders not to participate either," party's state president Dinesh Gundu Rao tweeted.
Noting that the swearing-in of Yediyurappa as chief minister was unethical and unconstitutional, based on horse trading and corrupt methods, Rao said the BJP forming the next government in the state was a blot on democracy.
Caretaker Chief Minister and JD-S leader H.D. Kumaraswamy has also decided to skip the event for personal reasons.
"Though Yeddyurappa has sent an invitation for the ceremony to Kumaraswamy and our other party leaders, many have decided to stay away for various reasons," JD-S spokesman Ramesh Babu told .
Earlier Babu tweeted in Kannada: "The #HorseTradingParty of India has staked claim to form government even though it doesn't have the magic number of 112."
Saying Friday marked one of the darkest days in the history of Karnataka, he tweeted: "Democracy is dying a slow death because of BJP's unconstitutional practices." He further added, "#HorseTraderYeddyurappa".
The Congress also slammed Yediyurappa tweeting that "he has used his excellent horse-trading skills to subvert democracy and come to power. History is set to repeat again".
Karnataka Congress Legislative Party (CLP) leader Siddaramaiah said: "Assembly has become an experimental lab for the BJP that doesn't have majority and its Governor to try unconstitutional ways to form government."
The JD-S also tweeted: "How did the state Governor allow in a minute to administer oath of office to Yediyurappa when his party (BJP) has only 105 legislators in the 222-member Assembly, with 112 as halfway mark for simple majority after 3 rebel Congress MLA were disqualified by the Speaker (K.R. Ramesh Kumar) on Thursday?"
Senior JD-S leader and former minster Basavaraj Horatti said Yediyurappa had no patience and his government's collapse was imminent. "The new BJP government will not last long. The rebel legislators who ditched the Congress and the JD-S are untrustworthy," Horatti told reporters at Hubballi.
Horatti, who was the chairman of the state Legislative Council for a few months after the coalition government was formed in May 23, 2018, claimed that while the secular allies JD-S and Congress had trouble shooters, the BJP had trouble makers. "It will have tough time in controlling the rebels," he added.
( With inputs from IANS )