Within days of the first protests, the anti-Qaddafi movement began to evolve into an armed rebellion as demonstrators acquired weapons from abandoned government arms depots. By late February, rebel forces had expelled most pro-Qaddafi troops from the eastern portion of Libya, including the city of Benghazi, and from many western cities. The Libyan-Egyptian border was opened, allowing foreign journalists into the country for the first time since the conflict began. Pro-Qaddafi paramilitary units continued to hold the city of Tripoli, where Qaddafi and his inner circle remained.

International pressure for Qaddafi to step down gradually increased. On February 26 the UN Security Council unanimously approved a measure that included sanctions against the Qaddafi regime, imposing a travel ban and an arms embargo and freezing the Qaddafi family’s assets. The measure also referred the case to the International Criminal Court (ICC). The United States, the European Union, and a number of other countries also imposed sanctions.

A rebel leadership council emerged in Benghazi in early March. Known as the Transitional National Council (TNC), it declared that its aims would be to act as the rebellion’s military leadership and as the representative of the Libyan opposition, provide services in rebel-held areas, and guide the country’s transition to democratic government.

Stalemate, resurgence of the Qaddafi regime, and international intervention

In the weeks that followed, the conflict appeared to enter a stalemate and then to tilt in Qaddafi’s favour. Despite the rebels’ impressive gains in February, the Qaddafi regime still controlled enough soldiers and weapons to hold Tripoli and to stage fresh ground and air assaults which rebel fighters struggled to repel. Most fighting took place in the towns around Tripoli and in the central coastal region, where rebels and Qaddafi loyalists battled for control of the oil-export terminals on the Gulf of Sidra.

The international community continued to debate possible diplomatic and military intervention in the conflict. Countries worked to establish contact with the TNC and in some cases began to recognize it as Libya’s legitimate government. At an emergency summit on March 11 the European Union unanimously called for Qaddafi to step down. However, the international community remained divided over the possibility of military intervention. Some countries, including France and the United Kingdom, sought the establishment of a no-fly zone over Libya to protect rebels and civilians from air attacks, while others, including the United States and Germany, expressed reservations, emphasizing the need for broad international consensus and warning against possible unforeseen consequences of military intervention. The African Union (AU) rejected any military intervention, asserting that the crisis should be resolved through negotiations, whereas the Arab League passed a resolution on March 13 calling on the UN Security Council to impose a no-fly zone over Libya.

On March 15 Qaddafi loyalists captured the eastern city of Ajdābiyā, the last large rebel-held city on the route to Benghazi. As they advanced on the remaining rebel positions in Benghazi and Tobruk in the east and Misurata in the west, the UN Security Council voted on March 17 to authorize military action, including a no-fly zone to protect Libyan civilians. Beginning on March 19, an international coalition led by the U.S., France, and the United Kingdom began to carry out air and missile strikes to disable Libya’s air force and air defense systems so the no-fly zone could be imposed. Coalition missiles also struck buildings in a compound used by Qaddafi as a command centre.

Within a week Libya’s air force and air defenses were out of commission. However, heavy fighting continued on the ground. Pro-Qaddafi units massed around the rebel-held city of Misurata and the contested city of Ajdābiyā, shelling both and causing significant civilian casualties. Attacks by coalition warplanes soon weakened pro-Qaddafi ground forces in eastern Libya, allowing rebels to advance and retake Ajdābiyā, Marsa el Brega, Ras Lanuf, and Ben Jawad.

Intensification of international efforts: NATO air strikes, diplomacy, and ICC warrants

On March 27 the North Atlantic Treaty Organization (NATO) officially took over command of military operations in Libya from the United States, France, and the United Kingdom. The handover came after several days of debate among NATO countries over the limits of international military intervention; several countries argued that the coalition’s aggressive targeting of pro-Qaddafi ground forces had exceeded the mandate set by the UN Security Council to protect civilians.

By April the conflict seemed to have returned to a stalemate; Qaddafi’s troops, though weakened by the coalition assault, still appeared strong enough to prevent the disorganized and poorly equipped rebels from achieving decisive victories. Diplomatic efforts to resolve the crisis intensified, with an AU delegation traveling to Tripoli on April 10 to present a cease-fire plan that was quickly rejected by both sides.

On April 30 a NATO air strike on a house in Qaddafi’s compound in Tripoli killed Qaddafi’s youngest son, Sayf al-Arab, along with three of Qaddafi’s grandchildren. Qaddafi was present at the site of the strike but avoided injury. More strikes in early May targeted government buildings associated with Qaddafi and Libya’s senior military leadership, but NATO representatives denied claims that NATO had adopted a strategy of trying to kill Qaddafi and other high-ranking Libyan officials.

International pressure on Qaddafi continued to build. The ICC, which in early March had opened an investigation into alleged war crimes by members of the Qaddafi regime, announced on May 16 that it would seek arrest warrants against Qaddafi, his son Sayf al-Islam, and the head of Libyan intelligence, Abdullah Senussi, for ordering attacks on civilians in Libya.