By Ann M. Simmons

MOSCOW -- Russian investigators have launched a criminal probe into a massive fuel leak from a power station in the Arctic after President Vladimir Putin publicly admonished a senior official over the incident and declared a national state of emergency.

The power plant operator said accidental damage to a diesel fuel storage tank in the remote Siberian city of Norilsk caused 20,000 tons of fuel to seep into the soil across a significant area and contaminate bodies of water.

Mining company Norilsk Nickel, or Nornickel, whose subsidiary Norilsk-Taymyr Energy Co. ran the facility, said the incident on May 29 followed the sudden failure of posts supporting the basement of the storage tank.

Russia's Investigative Committee, the country's main investigations agency, said the spill caused significant pollution and environmental damage.

The Russian branch of the international environmental organization Greenpeace said the damage to rivers and lakes nearby in Taymyr could exceed 6 billion rubles, or around $87 million.

"This doesn't take into account soil damage and emissions of pollutants into the atmosphere," the group said.

The company said it was too early to discuss the extent of the damage. "The assessment will be carried out after the completion of the cleaning and investigation," it said.

A court on Thursday announced the arrest the day before of Vyacheslav Starostin, the head of the power plant where the incident took place.

Investigators said they had opened three criminal cases on counts of "soil damage, violation of environmental regulations in the course of economic activity, and water pollution." A fourth case was opened on counts of negligence over the late reporting of the accident, the Investigative Committee said.

Mr. Starostin and his representatives couldn't immediately be reached for comment.

On Wednesday, during a televised government meeting to discuss measures to address the fuel spill, a visibly annoyed Mr. Putin scolded the region's governor on air, saying he was shocked that local authorities had become aware of the emergency situation only from social media and two days after it had occurred. In recent years he has sought to emphasize the importance of environmental issues.

"Is everything all right with your health there?" Mr. Putin said. "I will be forced to instruct law enforcement agencies to give a legal assessment of all the actions taken by officials."

Nornickel said the company had "duly reported the incident in a timely manner," and had provided law enforcement agencies with copies of official reports on the incident."

The Russian leader backed a proposal to declare a national state of emergency over the incident, which would allow for federal support for the cleanup effort. A regional state of emergency had already been declared, according to Alexander Uss, governor of Krasnoyarsk region, where the Nornickel plant is located.

The company, which describes itself as the world's largest producer of palladium and one of the largest producers of nickel, platinum and copper, said it "is actively working to eliminate the consequences of the incident." It said cleanup would take about two weeks.

Write to Ann M. Simmons at ann.simmons@wsj.com