MOSCOW — Ukraine’s national security service has released what it says are recordings of a Frenchman and a Ukrainian discussing plans for terror attacks in France, in which the Frenchman says targets would include the national tax center and a bridge.

The audio recordings, posted Wednesday on YouTube by the security service, follow Monday’s announcement that a Frenchman with an arsenal of weapons and a grudge against his government’s immigration policies had been detained as he tried to leave Ukraine and launch attacks tied to France’s hosting of the European football championships.

The security service, the SBU, provided no details of how the recordings were obtained.

The Frenchman, identified as Muto in transcripts of the English-language conversations, is recorded saying: “My objective is to conduct some operations that will touch all French people.”

Ukrainian agents had been following the man since December, and allowed him to buy five machine guns, two rocket-propelled grenade launchers, 125 kilograms (275 pounds) of TNT, 100 detonators and other arms, the SBU said when the arrest was announced.

He also bought 20 balaclavas before he was arrested at the Yahodyn border crossing between Ukraine and Poland last month, the service said.

In the recordings, the unidentified Ukrainian notes that the Frenchman was seeking enough explosives to cause “a big boom in Paris.” But the Frenchman assured him that the tax center would be targeted at night when “there is nobody in the office, so don’t care about this.”

He also says there are about 10 people in his group “for operations.”