The removal of four members of Union environment minister Bhupender Yadav’s personal staff, including his private secretary, in one unprecedented sweep has triggered intense speculation in Delhi’s political circles about more upheavals before a possible cabinet shuffle.

The buzz grew stronger with BJP president Nitin Nabin abruptly cutting short his visit to Jammu on Tuesday, during which a pilgrimage to the Mata Vaishno Devi shrine had been scheduled, and returning to Delhi to attend to what BJP sources described as “official commitments”. The party sources said he had been summoned for an “emergency meeting” in the capital, but declined to disclose its agenda.

The four officials attached to Yadav were either shunted or sacked through separate orders issued on July 3, though they came into the public domain only on Monday night and Tuesday. Never before in the Narendra Modi government’s 12-year tenure had an entire ministerial personal staff been removed in one stroke.

The government has offered no explanation for the action. However, sources said the purge was carried out on the directions of the Prime Minister’s Office, indicating that serious concerns had arisen over the functioning of the ministry headed by Yadav, one of the BJP’s most prominent OBC leaders and a key organisational strategist.

The ministry plays a key role as most industries have to secure environment clearance before setting up plants.

Yadav had assumed a high-profile political role in recent months,having served as the BJP’s principal election in-charge for the Bengal Assembly polls and later playing a key part in engineering the defection of 20 Trinamool Congress MPs.

Yadav has so far chosen silence on the removal of his personal staff.

The sources said similar action could follow in the offices of some other Union ministers as Prime Minister Modi prepares the ground for a wider overhaul of his government.

Nabin was in Jammu as part of his ongoing organisational outreach and was scheduled to address a “youth dialogue” and also visit the Mata Vaishno Devi temple, but curtailed his itinerary. An organisational shuffle has been pending since Nabin took over as party chief in January.

Environment minister Yadav’s private secretary, Amar Singh, an Indian Revenue Service officer of the 2010 batch, and additional private secretary Shailesh Kumar Singh have been repatriated to their parent cadre. Two others who were said to be political appointees have been dismissed with immediate effect.

The order on Amar Singh said he had been repatriated to the department of revenue “on administrative grounds” and “relieved of his duties with immediate effect”.

Two other orders terminated the services of additional private secretary Ayush Sharan Singh and additional assistant secretary Siddharth Yadav, considered a close aide of the minister.

Citing a July 3 office memorandum issued by the department of personnel and training and approval from the competent authority, the order said: “The appointment of Shri Siddharth Yadav… is terminated with immediate effect”.

While individual aides to senior ministers have been removed during the first two Modi governments, a simultaneous overhaul of the entire personal staff of a minister is learnt to have unsettled sections of the Union council of ministers. Insiders said the fear of being shunted out during the impending shuffle had gripped many.

“There is speculation that the personal staff of some more ministers could also come under scrutiny. The PMO is known to closely monitor ministerial offices, and reports of alleged irregularities involving some staff members have surfaced in recent months,” a BJP MP said.

Party insiders linked the action in Yadav’s office to heightened vigilance by the PMO following recent disclosures over land transactions involving members of Madhya Pradesh chief minister Mohan Yadav’s family in Ujjain.

Although the BJP publicly defended Mohan Yadav, maintaining that no wrongdoing had taken place, some party leaders privately believe that the controversy, coupled with the alleged embezzlement of donations at the Ram temple, had dented the central BJP dispensation’s anti-corruption credentials.

The sources said the churn could extend beyond the Union cabinet, with some chief ministers, including Mohan Yadav, also facing replacement. Sections within the BJP are speculating that Bhupender Yadav could be among those affected by the anticipated shuffle.

Bhupender Yadav was seen on Tuesday planting a sapling in Delhi with Union home minister Amit Shah as part of Modi’s Ek Ped Maa Ke Naam campaign. Yadav is widely regarded within the party as a Shah confidant.