WASHINGTON — A new wave of cyberattacks is striking American corporations, prompting warnings from federal officials, including a vague one issued last week by the Department of Homeland Security. This time, officials say, the attackers’ aim is not espionage but sabotage, and the source seems to be somewhere in the Middle East.

The targets have primarily been energy companies, and the attacks appeared to be probes, looking for ways to seize control of their processing systems. The attacks are continuing, officials said. But two senior administration officials said Sunday that they were still not certain exactly where the attacks were coming from, or whether they were state-sponsored or the work of hackers or criminals.

“We are concerned by these intrusions, and we are trying to make sure they don’t lead to something much bigger, as they did in the Saudi case,” said one senior American official. He was referring to the aggressive attack last summer that affected 30,000 computers at Saudi Aramco, one of the world’s largest oil producers. After lengthy investigations, American officials concluded that Iran had been behind the Saudi Aramco attack.

Another official said that in the new wave of attacks, “most everything we have seen is coming from the Middle East,” but he did not say whether Iran, or another country, appeared to be the source.