Israel carried out covert attacks on two major gas pipelines inside Iran this week, disrupting the flow of heat and cooking gas to provinces with millions of people, according to two Western officials and a military strategist affiliated with Iran’s Revolutionary Guards Corps.

The strikes represent a notable shift in the shadow war that Israel and Iran have been waging by air, land, sea and cyberattack for years.

Israel has long targeted military and nuclear sites inside Iran — and assassinated Iranian nuclear scientists and commanders — both inside and outside of the country. Israel has also waged cyberattacks to disable servers belonging to the oil ministry, causing turmoil at gas stations nationwide.

But blowing up part of the country’s energy infrastructure, relied on by industries, factories and millions of civilians, marked an escalation in the covert war and appeared to open a new frontier, officials and analysts said.

“The enemy’s plan was to completely disrupt the flow of gas in winter to several main cities and provinces in our country,” Iran’s oil minister, Javad Owji, told Iranian media on Friday.

Mr. Owji, who had previously referred to the blasts as “sabotage and terrorist attacks,” stopped short of publicly blaming Israel or any other culprit. But he said that the goal of the attack was to damage Iran’s energy infrastructure and stir domestic discontent.