The Countering Iran in the Western Hemisphere Act of 2012 would require the State Departmentto compile a detailed report for Congress on the activities and motivations of the Iranian Republican Guard, its elite Qods Force,Lebanon’s Hezbollah organization and the Palestinian militant group Hamas in Latin America.

The legislation has picked up 63 co-sponsors, all but two of them Republicans. But it gained notable bipartisan traction last week when the House Foreign Affairs subcommittee on terrorism, nonproliferation and trade approved it by verbal vote. It now goes to the full committee.

“The support of the subcommittee shows that Congress recognizes the seriousness of the threat that Iran poses to Americans here at home and to our allies in the Western Hemisphere,” said Rep. Jeff Duncan, South Carolina Republican.

The bill’s lead Democratic co-sponsor, Rep. Brian Higgins of New York, said that “issues brought to light during recent hearings raise serious concerns about potential threats to America including new evidence of activity dangerously close to home.”

Questions about covert Iranian activities in Latin America burst onto the political landscape in October, when the Justice Department filed charges revealing a failed plot by Iranian officials to use a Mexican drug cartel to assassinate a Saudi diplomat in Washington.

While many policy analysts and Democrats have expressed skepticism about the plot, the issue of Iran’s covert desire’s in the region has made its way back into the headlines during recent weeks.

Director of National Intelligence James R. Clapper recently told the Senate Select Committee on Intelligence that, if Iran feels threatened, it could seek to launch terror attacks against targets inside the United States.

His remarks were underscored by Michael Braun, former chief of operations and intelligence for the Drug Enforcement Administration (DEA), who told lawmakers that Iranian collaboration with Latin American drug cartels is growing “faster than most policymakers in Washington, D.C., choose to admit.”

Mr. Braun, who retired from the DEA in 2008, revealed details about a DEA campaign that year in which agents broke up a cocaine-smuggling and money-laundering ring believed to have been channeling funds to the Iranian-backed Lebanese militia Hezbollah.

Secretary of State Hillary Rodham Clinton told lawmakers last week that while her department is “concerned about allegations” of drug cartel links to Hezbollah and Iran, “we’ve not found information to verify a lot of the allegations.”

“But the recent incident concerning the attempted assassination of the Saudi ambassador is a very large question mark and wake-up call,” she told the House Foreign Affairs Committee.