Moammar Gadhafi's forces stepped up pressure near the port city of Misrata and a key western mountain range to try to block rebel fighters from advancing toward the capital of Tripoli, rebels said Tuesday.

At least 11 people were killed in the fighting that began late Monday and continued Tuesday, activists said.

Since the outbreak of the revolt against his regime nearly five months ago, Gadhafi has clung to areas of western Libya, while the rebels have entrenched themselves in the eastern third of the country. Libyan government troops have been unable to retake two main rebel strongholds in the west _ Misrata and several towns in the Nafusa mountain range. The rebels have been trying to break out of these bridgeheads and advance toward Tripoli.

In the latest round, fierce fighting was reported in the town of Dafniya, near Misrata, with seven rebels killed and 46 wounded, said anti-government activist Faraj Akwedeir. Gadhafi's troops "tried to enter Misrata from several fronts but our fighters stopped them," he said.

Government troops also fired rockets and mortars at the town of Kikla, southwest of Tripoli, said Abdel-Salam Othman of the Nafusa mountain military council. He said four people were killed and eight wounded in fighting there.

Gadhafi's forces have entered schools and mosques in Kikla to hide weapons, he said. "They even raise our flags to deceive the NATO," he added, referring to the rebels' tricolor. Libya's national flag is green.

The western towns of Zintan and Nalut have come under attack as well, Othman said. "Gadhafi forces failed to advance but they keep putting pressure to stop us," he added.

Over the past few weeks, rebel fighters have gathered on the outskirts of the town of Bair al-Ghanam, some 50 miles (80 kilometers) from Tripoli. Control over Bair al-Ghanam would open the road to the capital. "We are consolidating force there and we are waiting for the people in Bair al-Ghanam to ensure us that they are not going to open their houses to Gadhafi troops," Othman said.

A popular uprising against Gadhafi erupted in Libya in mid-February and quickly turned into armed conflict when peaceful protests were met by a deadly crackdown.

NATO has been carrying out airstrikes against Gadhafi-linked military targets since March. It is joined by a number of Arab allies, including the wealthy Gulf states of Qatar and the United Arab Emirates.