The Germans are searching for at least 10 more suspects in the terror plot against Frankfurt Airport and Ramstein Air Base.

KARLSRUHE , Germany , Sept. 6 — German investigators were searching today for 10 suspects in connection with a foiled terrorist attack on German and American targets by Islamic militants, officials said.

The suspects are believed to have provided support to the three main suspects in the plot, according to August Hanning, the deputy interior minister and a former head of Germany’s foreign intelligence service, the B.N.D. Their arrests were announced Wednesday, a day after they were captured in a raid in western Germany. …

Tuesday’s raid brought to an end months of undercover surveillance operation during which German agents had monitored the suspects closely. Authorities seized large quantities of hydrogen peroxide, which can be mixed with other chemicals to make explosives, and military-grade detonators. The three men arrested were two German citizens who had converted to Islam and a Turkish resident of Germany. The police and security officials said they attacks they were planning could have been deadlier than those that killed dozens in London and Madrid. …

Among the 10 men still at large are some German converts to Islam, some Turkish residents of Germany and also other nationalities, Mr. Hanning said today.

According to an official close to the investigation, at least one of the men is Pakistani, another Lebanese and some are stateless. At least one of them left Germany by plane to go to Turkey, but he may since have traveled on by land, the official said, who declined to be identified because the investigation is still ongoing.