Peter Bouckaert, emergencies director at Human Rights Watch, said, in a statement, that it was "disturbing" that the Transitional National Council hasn't yet secured the country's weapons storage facilities.
Tripoli fell into rebel hands in late August. War crimes fugitive Moammar Gadhafi, Libya's bombastic leader, remains on the run.
NATO spokeswoman Oana Lungescu said Aug. 23 that Gadhafi was "history." But the launch of a Scud missile against Misurata the previous day suggested the fight wasn't over.
Human Rights Watch said there were lingering concerns about Libya's weapons after it toured several storage facilities last week.
"Thousands of weapons such as surface-to-air and antitank missiles are missing and many facilities are being plundered," added Bouckaert.
U.S. and European officials have expressed concerns over the security of weapons stockpiles in Libya. Al-Qaida in the Islamic Maghreb, al-Qaida's North African branch, may have taken some of the weapons, European officials said.
A U.S. military official told The New York Times, on condition of anonymity, last week that the weapons situation was "murky" because they haven't been any major weapons attacks on NATO forces, which continue to operate in the skies over Libya.