"This decision is both unfortunate as well as unilateral. It's a decision; I am afraid, will be construed as being guided wholly & solely by political considerations instead of developmental concerns," Mr Shah has written in his letter.
"It is widely known that the Union Government led by Hon'ble Prime Minister Shri Narendra Modi has left no stone unturned in ensuring the growth and prosperity of Andhra Pradesh," the letter added.
The TDP, once the BJP's biggest ally in south, pulled out of the government earlier this month over the special status demand. The first formal exit of an ally is a psychological blow for the BJP on the back of its by-poll disaster in Uttar Pradesh and Bihar; the party was stunned as it lost two strongholds in UP.

TDP exited the NDA alliance over the centre's reluctance to grant special category to Andhra Pradesh
While most opposition parties, including the Congress, announced support for the motion, the government has the numbers to remain safe. The NDA's strength is still 315 in the 543-member house, way above the half-way mark of 272. The opposition says the move is about sending a message.
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Assembly elections are due in Andhra Pradesh next year and regional parties in the state, including the YSR Congress, have repeatedly targeted the TDP for being unable to secure a special category status for the state. The tag would have meant a greater infusion of central funds, something that was promised by the centre earlier.The demand for the special category status for the southern state has been a big issue ever since the bifurcation of the state which gave birth to Telangana 2014. Mr Naidu said Andhra was promised a special category status, but the centre has refused what it was promised.
"The decision of TDP to quit NDA is unfortunate as well as unilateral, wholly and solely guided by political considerations instead of developmental concerns of Andhra Pradesh", Shri @AmitShah writes an open letter to Andhra Pradesh CM Chandrababu Naidu https://t.co/M9M4tsisUY
- BJP (@BJP4India) March 24, 2018