The supply of gasoline in the United States has tightened and the country is being pushed into a fuel crisis as the shut down of one of the major pipeline companies in the country enters its fifth day.

Colonial pipeline has said it has been working "substantially" to resume operations by the end of the week after its system was a victim of a cyberattack.

The top U.S. energy regulator issued a call on Monday for mandatory cybersecurity standards for pipeline operators. “Encouraging pipelines to voluntarily adopt best practices is an inadequate response,” said Federal Energy Regulatory Commission Chair Richard Glick.

The FBI has accused a shadowy criminal gang called DarkSide of the ransomware attack. DarkSide is believed to be based in Russia or Eastern Europe, according to cyber experts, who point out that it avoids targeting computers that use languages from former Soviet republics.

The top U.S. energy regulator issued a call on Monday for mandatory cybersecurity standards for pipeline operators. “Encouraging pipelines to voluntarily adopt best practices is an inadequate response,” said Federal Energy Regulatory Commission Chair Richard Glick.

The FBI has accused a shadowy criminal gang called DarkSide of the ransomware attack. DarkSide is believed to be based in Russia or Eastern Europe, according to cyber experts, who point out that it avoids targeting computers that use languages from former Soviet republics.

The American Automobile Association said the national gasoline price average climbed 6 cents on the week to $2.96 a gallon, the highest since May 2018, and was approaching the highest level since 2014. But it warned against hoarding, saying that thins supplies further.