Tripoli, Libya (CNN) -- Efforts to prevent forces loyal to Libyan leader Moammar Gadhafi from attacking civilians have been complicated by weather and the regime's decision to hide military equipment in populated areas and to use human shields, NATO Brig. Gen. Marc van Uhm said Tuesday.
Rebel leaders have criticized NATO's efforts in recent days, saying civilians and rebel forces in Misrata and elsewhere have suffered under hellish attacks from pro-Gadhafi forces, with little evidence of NATO air power overhead.
"I am extremely sorry to say this, but NATO truly disappointed us," said Gen. Abdul Fatah Younis, the opposition's top military official. "If NATO wanted to free Misrata, they could have done that a few days ago."
Five people were killed and 24 wounded in Monday clashes between pro-Gadhafi forces and rebels in Misrata, two sources told CNN.
Residents have said Gadhafi troops had choked off the city from electricity and access to food.
"Every day, life is getting more and more difficult," said one resident, who is not being identified for safety reasons. "There are long queues of people for bread and fuel."
Some are not leaving their homes for days at a time, he added.
"There are snipers shooting at anything that moves," the resident said. "They are controlling the main road leading to outside the city."
Younis said NATO's concerns about collateral damage are unfounded.
"The region where the Gadhafi forces are is not inhabited by civilians. Anyway, civilians are being killed every day, including children, women and elderly," he said. "If NATO will wait another week, Misrata will be finished. No one will be left alive. Do they want to wait, and watch them die, and let this crime be a shameful disgrace for the international community forever?"
Rebel spokesman Abdul Hafiz Ghoga also blamed Turkey for an alleged drop-off in air strikes.
Van Uhm, chief of allied operations at NATO, defended the organization's efforts, saying warplanes under NATO command flew 58 strike missions Monday, firing weapons and striking pro-Gadhafi targets on 14 of them.
He did not immediately have figures for previous days, but NATO spokeswoman Oana Lungescu said the warplanes had conducted 334 strike sorties since taking command of the mission on March 23.
"I think you can safely say the operational tempo continues unabated," she said.
In addition to using human shields and hiding equipment in populated areas, pro-Gadhafi forces have begun abandoning heavy military equipment in favor of the same kinds of cars and light trucks the rebels travel in, making it even more difficult for pilots to distinguish rebel convoys from those carrying forces loyal to the regime, van Uhm said.
Since the effort to enforce the U.N. resolution began in mid-March, airstrikes have taken out about 30% of Gadhafi's military capacity, van Uhm said.
Monday's airstrikes hit an active rocket launcher in al-Brega, an air defense installation and military vehicles near Misrata as well as ammunition storage facilities, van Uhm said.
But Gadhafi's forces appeared to have the upper hand Tuesday in renewed fighting in al-Brega, where rebel forces were staging a panicked retreat under intense artillery bombardment, according to CNN reporters in the area.
The setback is the latest for a ragtag opposition that has struggled to maintain ground against the better-trained and -equipped Gadhafi forces, and it comes less than a day after rebel commanders said they had the longtime Libyan leader's forces on the defensive in al-Brega.
With no end to the war in sight, a source close to the country's leadership said a Libyan envoy is floating the idea of Gadhafi passing his power to a son -- a notion rebel leaders deem merely cosmetic.
Under the proposal, Saif al-Islam Gadhafi, 38, would help to usher in reform, the source said. However, Saif Gadhafi has become one of his father's most outspoken defenders since the start of the unrest despite once being perceived as a leading reformer in the Libyan government.
A proposal to shift power from Gadhafi to his second-oldest son is "a ridiculous offer," said Ali Aujali, a former Libyan ambassador to the United States who now represents the Libyan opposition in Washington.
"Libyan people, they decided, and they will not go back at all (to) Gadhafi or any member of his family," Aujali said. "His sons, they are killers -- they're just like their father."
Aujali said rebels are willing to offer Moammar Gadhafi and his family safe passage out of Libya in an exchange for an end to the fighting -- but that's as far as their offer goes.
Though Gadhafi has shown no signs of appeasing the opposition or relinquishing his power to anyone outside his family, cracks in his armor have surfaced.
His longtime confidant and foreign minister, Moussa Koussa, recently fled to London and announced his resignation from the Libyan government. On Monday, the U.S. Treasury Department lifted the freeze on Koussa's assets following his split from Gadhafi.
On Tuesday, Deputy Foreign Minister Khalid Khaim confirmed reports that Abdelati Obeidi is the nation's new foreign minister.
Rebel spokesman Mustafa Gheriani said while the conflict persists, he remains hopeful for a revolution.
"I think the Gadhafi regime is crumbling from within," he said. "I think if you look at history, people will always win, and I think victory will be ours."
CNN's Nic Robertson, Reza Sayah, Ben Wedeman, Brian Todd and Yousuf Basil contributed to this report