Uddhav Thackeray's Shiv Sena has been critical of the BJP and its top leadership over several issues.
The BJP's warring ally Shiv Sena on Tuesday chose to stay away from the inauguration of various projects by Prime Minister Narendra Modi in Mumbai and Pune.
PM Modi on Tuesday laid the foundation stones for two metro lines- Thane-Bhiwandi-Kalyan (Metro 5) and the Dahisar-Mira Bhayander (Metro 9) at Kalyan in neighbouring Thane district. He also launched the Navi Mumbai town planning authority Cidco's (City & Industrial Development Corporation (Cidco) mass-housing scheme worth Rs 18,000 crore.
Later, PM Modi also laid the foundation stone of the phase three of the Pune Metro.
A senior Shiv Sena leader said since the party chief Uddhav Thackeray was not invited to PM Modi's events, Sena leaders and ministers decided to boycott his functions.
"After we learnt that Uddhav Thackeray has not been invited, the party leaders decided to boycott all the functions of PM Modi in Maharashtra on Tuesday," he said.
According to a BJP leader, an editorial in Shiv Sena's mouthpiece Saamana had not gone down well with his party's leadership.
"There was a direct attack on Narendra Modi in an editorial in Saamana. Holding PM Modi responsible for the BJP's loss of power in three states has not gone down well with our leadership in the state as well as at the Centre," he said.
Senior BJP leader and state Education Minister Vinod Tawde said, "We had invited everyone to the PM's functions as per the protocol. The ministers from Thane district and even members of Parliament (MPs) were invited."
The minister hinted that Mr Thackeray was not invited as he did not hold any constitutional post.
Another Shiv Sena leader, however, pointed out that Mr Thackeray had been invited for the foundation laying ceremony of Shivaji memorial attended by PM Modi in Mumbai two years back.
"Mr Thackeray was invited to the function where the prime minister was present. He had even sat on the stage," he said.
"If protocol is so important, then why does the BJP interpret it as per its own convenience?" the Shiv Sena leader asked.
On Sunday, Uddhav Thackeray had performed the bhumi-pujan, or the ground-breaking ceremony, for the Rs 12,000-crore coastal road project, which no BJP leader or minister attended.
A BJP leader had claimed that there was no invitation to even Maharashtra Chief Minister Devendra Fadnavis for the function organised by the Brihanmumbai Municipal Corporation, ruled by the Shiv Sena.
Almost a year back, Mr Thackeray had announced that his party would contest all the future elections alone. Shiv Sena has been critical of the BJP and its top leadership over several issues.
However, the BJP has been consistently terming Shiv Sena as its natural ally and warning it that contesting the polls separately could benefit the opposition parties.