Chief minister Mamata Banerjee was admitted to hospital with multiple injuries to her left ankle, hip and the region around the collar bone, suffered when a group allegedly slammed the door of an SUV on whose footboard she was standing to greet people after filing her nomination for the Nandigram seat on Wednesday.

Late on Wednesday night, an MRI scan showed a crack in the left foot, and ligament and soft tissue injuries, sources said.

“I was standing on the footboard of the car to greet the crowd when four to five people suddenly slammed the door (of the car). See how my feet have swollen. It’s a conspiracy.... It was deliberate,” Mamata, who was clearly in severe pain, said in Nandigram.

“There was no one from the local police. The SP was not there, either,” she added, sitting in the front seat of the SUV.

As Mamata was feeling nauseous, a green corridor was created and she was rushed to Calcutta for admission to SSKM Hospital. A five-member medical board has been set up.

The incident injected an unexpected element into the election discourse, with some Opposition leaders such as the BJP’s Arjun Singh calling it “drama”.

Several other leaders, including railway minister Piyush Goyal, echoed him and suggested that Mamata’s allegations stemmed from the realisation that she would lose from Nandigram.

By night, however, some in the BJP appeared to have realised that the barbs were in poor taste and might backfire at the hustings.

Governor Jagdeep Dhankhar visited SSKM. “Sought an update from Director, Security and Chief Secretary in matter. Health Secretary and Director of Hospital urged to take all caution,” Dhankhar tweeted.

The police administration in the state is now under the Election Commission as the polls have been notified. The Election Commission has sought a report on the incident.

“Such statements from BJP leaders are in poor taste…. The country’s lone woman chief minister suffers injuries and they make such comments,” said Trinamul MP Saugata Roy.

The chief minister complained of excruciating pain when doctors met her at cabin number twelve-and-a-half in the Woodburn Ward of SSKM Medical College and Hospital. She was given painkillers and had X-rays taken. From SSKM, she was taken to the Bangur Institute of Neurosciences next door for the MRI scan.

“The chief minister complained of nausea and was clearly in severe trauma,” a doctor said. “She was stabilised immediately after admission.”

Several Trinamul leaders, many of whom had rushed to SSKM in the evening, iterated the conspiracy charge. Good wishes for Mamata poured in from different parts of the country.

Delhi chief minister Arvind Kejriwal tweeted: “I strongly condemn the attack on Mamata Didi. Those responsible should be immediately arrested and punished. I pray for her speedy recovery.”

Samajwadi Party leader Akhilesh Yadav expressed concern and demanded a probe.

Poll observer Vivek Dubey said the police would conduct an investigation after recording the chief minister’s statement.

Mamata had a busy day in Nandigram on Wednesday. She filed her nomination in Haldia and then visited several places of worship, participated in programmes and interacted with ordinary voters.

Before her injury, she had planned to spend the night in Nandigram.

Local sources said the incident took place while Mamata was leaving the Giribazar area of Rani Chowk in Nandigram after visiting a temple.

“The place was very crowded: around 5,000 people were waiting when she came out of the temple.… Seeing the crowd, she stood on the footboard to greet the people. Suddenly, she fell down and then we heard her cry out in pain,” an eyewitness said.

“Her security guards lifted her and placed her in the car. She was writhing in pain.… She was being taken to a rented accommodation in the Reyapara area of Nandigram when she complained of excruciating pain. A swelling had developed around her left ankle. Her security guards got ice cubes from an ice cream shop and applied them to the swelling.”

The alleged attack on Mamata and her accusations about the absence of local police threw up questions about her security, which counts as Z-plus.

Sources in East Midnapore police said the crowd had been beyond control through the day, with the chief minister travelling around Nandigram after filing her nomination.