TRIPOLI, Libya -- Libyan authorities boarded a renegade oil tanker and detained three militiamen and the crew after the vessel anchored off the country's coast Sunday, the state news agency and a Libyan navy spokesman said.

He also suggested that Libya might have tried to sink the ship had the Americans not boarded it on Tripoli's behalf.

U.S. Navy SEALs seized the Morning Glory last week in the eastern Mediterranean. That operation brought an end to an attempt by a militia from eastern Libya to sell the crude in defiance of the central government in Tripoli.

The oil, estimated at around 350,000 barrels, was to be unloaded later when the tanker moves on to the port of Zawiya refinery, 40 kilometres (25 miles) west of Tripoli.

The U.S. Navy handed over control of the tanker to Libyan forces Saturday while in international waters.

Libyan navy spokesman Ayoub Qassem told The Associated Press the tanker was boarded by members of the navy as it anchored off Tripoli. The sailors then arrested the 21-man crew and the three militiamen and took them to shore where they would be questioned by police.

The tanker's evasion of Libyan forces after loading oil from a terminal controlled by the eastern militia was an embarrassment to the weak central government. Parliament ousted the prime minister in the aftermath.

Col. Reda Eissa who had led efforts to retrieve the tanker said at a news conference that "bad weather and lack of capacity" prevented the Libyan navy from stopping it.

Qassem, the navy spokesman, also said that "a decision had been made to destroy the tanker Morning Glory, but United States intervention came to protect life and the environment."

The tanker's return could help bolster the authority of the weak central government in the face of the country's powerful militias. It is also a manifestation of the West's support for the government in its struggle to rein in the militias as well as its concern over the fate of the energy-rich North African nation.