WASHINGTON — Air security is expected to tighten, particularly for international flights into the United States, in light of recent intelligence that terrorists might be considering boarding flights with surgically implanted explosive devices, an American security official said Wednesday.

The Department of Homeland Security has warned foreign counterparts of the potential threat, the official said, speaking on ground rules of anonymity.

Efforts to smuggle explosives onto flights in undergarments and in printer cartridges have been traced back to the Al Qaeda affiliate in Yemen, but the official would not discuss the focus or origins of the latest intelligence.

But one senior Homeland Security Department official said that the new intelligence originally surfaced about a month ago, had been vetted since then and appeared to be linked to Al Qaeda in the Arabian Peninsula. “The new intelligence indicated at least a fresh look at this possible tactic” by the terrorist group, this official said.