KIEV, June 8 - Ukraine's security service SBU on Wednesday released audio recordings of a Frenchman that had been allegedly seeking to buy weapons and explosives in the country for terror attacks in France.

The targets mentioned by the Frenchman, who was only identified in transcripts as Muto, included the national tax center and a bridge.

The recordings were made of conversations between Muto and an unidentified Ukrainian who may have been an undercover security agent.

The release comes a day after French investigators said the Frenchman detained in Ukraine with a cache of weapons and explosives was more likely involved in arms smuggling than tied to a militant group.

In the recordings posted on the official YouTube page of the SBU, the Frenchman said in English language that he wanted to launch an operation that would have a massive impact.

“My objective is to conduct some operations that will touch all French people,” he said.

Ukrainian security agents had been following the man since December 2015, 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 on Monday.

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

In the recordings, the 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.”

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

Thomas Pison, the state prosecutor for Nancy, told Reuters on Tuesday that the Frenchman was not known to the authorities as a potential terrorist threat.

"This young man is unknown to French intelligence services, and the judicial authorities for now are leaning towards a possible arms smuggling case," Pison said.

The developments come days before a major Euro 2016 soccer tournament, which kicks off in France on Friday. (nr/ez)