At least 26 people are so far known to have died in an accident near Bhadeuna village in Uttar Pradesh's Kanpur district.
A tractor trolley carrying around 50 people overturned and fell into a pond on Saturday evening. The area falls under Saar Police Station's jurisdiction.
District Magistrate Vishak G Ayyar said most of the victims were women and children. It's feared that the death toll could rise.
He said the the tractor-trolley was on its way to Ghatampur after the passengers attended a "mundan" ceremony at the Chandrika Devi temple in Fatehpur, adding that that more than a dozen people were killed on the spot.
Prime Minister Narendra Modi and Chief Minister Yogi Adityanath have expressed grief over the incident.
"Distressed by the tractor-trolley mishap in Kanpur. My thoughts are with all those who have lost their near and dear ones. Prayers with the injured. The local administration is providing all possible assistance to the affected," said the Prime Minister's Office (PMO).
The PMO further quoted Modi as saying that an ex-gratia of Rs. 2 lakh from Prime Minister's National Relief Fund would be paid to the next of kin of each of the deceased and the injured would be given Rs. 50,000
Adityanath has sent ministers Rakesh Sachan and Ajit Pal to the accident site to speed up the rescue operation. He also appealed to people to use tractor-trolleys only for purposes related to farming and transferring goods and not for carrying passengers, according to an official release issued in Lucknow.
An eyewitness told reporters that he, along with others, rushed to the site hearing the cries of men, women and children for help.
The locals immediately jumped into the water and somehow managed to pull out the victims, some of whom were already dead, he said.
The injured were taken to the community health centre (CHC) at Bheetergaon, where some of them were declared brought dead, he added.
GSVM Medical College Principal Sanjay Kala told reporters that several of the injured have been referred to the Lala Lajpat Rai (LLR) Hospital.
According to officials , the injured were first rushed to the Bheetergaon CHC in ambulances arranged by police and more than a dozen were declared dead at the facility.
A government spokesperson in Lucknow said Adityanath is personally monitoring the rescue operation and has announced an ex-gratia amount of Rs 2 lakh each for the kin of the deceased and Rs 50,000 each for those seriously injured.
"An investigation is on to ascertain the reasons behind the accident," said DM Ayyar, adding that the district administration has been told to carry out the rescue operation and ensure all possible assistance to the victims.
In a tweet, Adityanath said: "The road accident in Kanpur district is heart wrenching. The district magistrate and other senior officers have been directed to reach the spot immediately, conduct the relief-and-rescue operations on a war footing and make arrangements for the proper treatment of the injured.
"The loss of lives in the accident is very sad. My condolences are with the bereaved families. Praying to Lord Ram to grant the departed souls a place at his feet and courage to the families of the deceased to bear this unfathomable loss."
Samajwadi Party (SP) President Akhilesh Yadav and Bahujan Samaj Party (BSP) President Mayawati have also expressed grief over the loss of lives in the accident.
In a tweet, Yadav said: "In Uttar Pradesh, transportation in tractor trolleys is continuously going on. The transport department is oblivious and innocent lives are being lost. The BJP government should take cognizance and carry out the rescue operation. Condolences on the deaths. The government should give a compensation of Rs 50 lakh to the relatives of the deceased, Rs 5 lakh to the injured and make arrangements for their treatment."
Mayawati conveyed her condolences to the bereaved families and asked the government to extend all possible help to the victims.
In a similar accident on the outskirts of Lucknow recently, 10 people were killed and 37 injured when the tractor-trolley in which they were travelling overturned.
(With PTI inputs)