Paraguay needed a military shake-up to create opportunities for young officers with a proven commitment to democracy, President Fernando Lugo said Friday in his first explanation for removing his top commanders this week.

Lugo named new army, air force and navy commanders Wednesday without explanation _ a day after denying he had worries about a coup amid calls for his impeachment.

In an interview with CNN on Friday, Lugo warned there could be a small group of officers influenced by politicians seeking to stage a coup to undermine his agenda.

But the reshuffling was intended to bring in new blood, he said.

"There are excellent young officers who must be given the opportunity," Lugo said. "Talented officers who have demonstrated their ability and track record at the same time in defending the country's democratic institutions."

Lugo, a left-leaning former Roman Catholic bishop, has struggled with the oppositioin-controlled Congress over implementing economic and social changes.

He sought to end speculation about a coup, declaring his actions were his own and should not be subject to speculation. Gen. John Oscar Velazquez, the army commander who was one of the three officers relieved of his duties Wednesday, was named chief of the armed forces Friday.