Tripoli, Libya ? Libya received its nuclear technology from a “sophisticated” international network but not necessarily with the knowledge of any government, the U.N. nuclear chief said after touring four atomic sites and meeting Monday with the country’s leader, Moammar Gadhafi.

Mohamed ElBaradei also said Libya’s technology was of a “familiar design” — meaning its origins would not be hard to trace — and that its nuclear program was not advanced. “What we have seen is a program in the very initial stages of development,” he said.

The United States, which believes Libya’s weapons programs are more extensive than the U.N. agency presumes, will send its own experts to help dismantle the programs, a senior Bush administration official told The Associated Press on Monday. The CIA and British intelligence believes there are 11 sites in Libya connected to weapons work, the official said.

In their talks, Gadhafi assured ElBaradei that Libya would cooperate fully with the International Atomic Energy Agency and eliminate its long-secret nuclear program, saying he wanted to turn Libya into a “mainstream” nation, IAEA spokesman Mark Gwozdecky said.

Gadhafi’s admission this month that Libya had been seeking nuclear weapons and his decision to renounce them — made after months of secret negotiations with the United States and Britain — came as a surprise to the IAEA, the U.N. body charged with keeping watch on nuclear programs.

ElBaradei and an IAEA team on Sunday toured four nuclear facilities in Tripoli, finding equipment dismantled and packed into crates. ElBaradei said that based on what the team saw, Libya reached only an experimental level in its attempts to enrich uranium, the essential material for a nuclear bomb.

“We haven’t seen any enriched uranium,” he told reporters. “We haven’t seen any industrial-scale facility to produce highly enriched uranium.”

It would have been “a question of years, not a question of months” before Libya could have produced weapons-grade uranium, ElBaradei said in an interview with CNN.

ElBaradei reported to the IAEA that there “wasn’t any weaponization” in Libya and that Iran’s nuclear program “was far more advanced.”

Iran insists that its nuclear program is for energy development only and intends to continue it. This month, it opened up previously secret parts of the program to IAEA inspection.