Senior lawmakers said they would investigate the government's purchase and use of powerful spyware made by two Israeli hacking firms as Congress passed a measure to try to rein in the proliferation of the hacking tools.

The head of the Drug Enforcement Administration was sent a letter by the chairman of the House Intelligence Committee asking for information about the agency's use of a tool.

Such use could have implications for U.S. national security as well as run contrary to efforts to deter the broad proliferation of powerful surveillance capabilities to autocratic regimes.

The Israeli hacking tool Pegasus can be used to penetrate the mobile phones of its targets. The New York Times reported that the D.E.A. was using Graphite.

The D.E.A. administrator was asked to respond by the end of the month.

The Republicans will take control of the House and Mr. Schiff will no longer be the chairman. The committee has bipartisanship so it is unlikely that the changeover will affect its agenda on this issue.

Commercial software has given countries around the world new powers to spy on their citizens. The Israeli firm NSO held a near monopoly in the industry for a long time, but new companies have found success as demand has exploded.

Congress passed a bill this month that gives the director of national intelligence the power to prevent the intelligence community from buying foreign spyware, and requires the director of national intelligence to submit a yearly watch list of foreign firms that pose a risk to American intelligence agencies.

Ron Wyden, an Oregon Democrat on the Senate Intelligence Committee, is pressing the Federal Bureau of Investigation for information about the bureau's purchase and testing of NSO's products. autocratic and democratic governments have used the Israeli firm's hacking tools to target journalists.

The Times reported last month that internal F.B.I. documents show that the criminal division drew up guidelines for using Pegasus before the F.B.I. decided against using it in operations.

The F.B.I.'s director was asked by Mr. Wyden if the bureau's lawyers made a determination that would preclude the F.B.I. from deployment.

Mr. Wyden wrote that the American people have a right to know the scale of the F.B.I.'s hacking activities.

Even though the F.B.I. decided not to deploy the tool in support of criminal investigations, it doesn't mean it wouldn't test, evaluate and possibly deploy other similar tools.

NSO and another Israeli hacking firm were placed on a Commerce Department blacklist, prohibiting American companies from doing business with them.

The Israeli hacking industry has been buffeted by a decision by Israel's ministry of defense to reduce the number of countries in which companies can sell their hacking tools. According to a senior Israeli military official, only six offensive tech firms will remain in Israel after the NSO blacklisting.

Two Israeli military officials who spoke on the condition of anonymity to discuss sensitive decision-making said that Israel's defense ministry appears to be considering easing restrictions on companies in order to keep the industry alive.

The goal is to improve the monitoring of controlled cyber exports and to create more precise instructions for controlled cyber exports, while reducing the risk of improper use of these systems, according to a spokesman for the defense ministry.

The Israeli government requires all hacking firms in the country to get an export license. Some Israelis have moved their businesses outside of Israel in order to escape the restrictions.

One of them, the retired Israeli general Tal Dilian, set up businesses in Greece and Cyprus, and his hacking tool is at the center of a widening scandal involving allegations of espionage.

The business of Israelis in other countries is not regulated by the Israeli government. The Israeli defense ministry convened a meeting to look into ways to better regulate Mr. Dilian and others who work outside of Israel. It was possible that an investigation could be opened into Mr. Dilian, or that other measures could be taken against Israeli hackers.