WASHINGTON — The commander of NATO’s air campaign in Libya has said that hundreds of organized fighters loyal to Col. Muammar el-Qaddafi pose a “resilient and fierce” threat in the two remaining pro-Qaddafi strongholds, and are exploiting the urban settings to complicate the alliance’s mission to protect civilians.

In the coastal city of Surt and the desert enclave of Bani Walid, pro-Qaddafi snipers on rooftops and loyalist gunmen in pickup trucks are terrorizing residents, killing some and intimidating many others, said the officer, Lt. Gen. Ralph J. Jodice II of the United States Air Force.

General Jodice said a mix of African mercenaries and Qaddafi loyalist troops have successfully sustained command-and-control and supply lines in staunch defense of the cities, despite a NATO air campaign that is now in its seventh month and a multipronged ground assault in Surt by anti-Qaddafi fighters.

“It’s really been quite interesting how resilient and fierce they’ve been,” General Jodice said in a telephone interview on Sunday from his command center just north of Bologna, Italy. “We’re all surprised by the tenacity of the pro-Qaddafi forces. At this point, they might not see a way out.”