Addressing Sena workers at the 52nd foundation day of the party in suburban Goregaon, Mr Thackeray said the BJP spread "lies" ahead of the 2014 general elections and made false promises to win people's mandate.
Shiv Sena runs the government in Maharashtra in alliance with the BJP, but their ties have remained fraught. They recently fought by-elections in Maharashtra separately.
Speaking about Prime Minister Narendra Modi's overseas visits, Mr Thackeray said, "(Prime Minister) Modi will soon start tours to other planets." He also hit out at the BJP's decision to withdraw support to the PDP-led government in Jammu and Kashmir.
"Did you need three years and the sacrifice of 600 jawans to realise that this government was useless?", Mr Thackeray said, questioning the decision to announce a ceasefire during the month of Ramzan.
If terrorism had nothing to do with religion, why such a ceasefire was announced, he asked.
"Does Pakistan follow a similar policy during Ganpati festival or Dussera?" the Shiv Sena chief asked.
Commenting further on the BJP's break-up with the PDP, he said: "When a similar divorce took place with us (ahead of the 2014 assembly polls in Maharashtra), you did not take so much time."
Shiv Sena and BJP fought the assembly elections separately, but formed alliance after the results were declared.
"We never gave up on our ideology. If we lose power, we will regain it. But will never back down on our ideology. The government with which you broke up today had not announced the ceasefire. It was announced by the Centre,", he added.
"You have broken up with PDP, now you can crush Pakistan. We will hail you (if you manage to do it)," he said.
The Sena chief also opposed the Citizenship (Amendment) Bill of the Centre. Earlier in the day, his party had supported the Asom Gana Parishad's stand on the issue.
"If the BJP is pushing for this bill, Shiv Sena MPs will oppose it. Why should we add more issues to worry about when we already have many. Why can't similar bill be presented for Kashmir?" he said.
The Sena chief asserted that the next chief minister of Maharashtra would be from his party.
"General elections may be held in December, hence the monsoon session of Maharashtra legislature is being held in Nagpur (instead of Mumbai, as is the custom). If there are some schemes for Vidarbha, then Shiv Sena will support it," Mr Thackeray said.
Mr Thackeray also slammed NCP chief Sharad Pawar, saying he was dividing Marathi people.
Mr Pawar recently stirred up controversy at a function when he said his party should prefer the 'Paagote' such as the one used by social reformer Jyotirao Phule, and not the 'Puneri Pagdi' associated with Brahmin scholars.
"Wearing a Pagdi does not make you Lokmanya (Tilak) or Phule... You have aversion to Tilak's Pagdi but you wear a special fur cap for Iftar," Mr Thackeray added.
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