Tripoli , Libya ( CNN ) -- From the halls of Congress to the shell-pocked streets of Libyan cities , intertwined themes rang clear Thursday : Leader Moammar Gadhafi is determined to prevail , and the opposition needs more training and allied air strikes to have a chance . `` Gadhafi will `` kill as many ( people ) as he must to crush the rebellion , '' Joint Chiefs of Staff Chairman Adm. Mike Mullen told the House Armed Services Committee . The rebels , who were regrouping after several setbacks , pinned their hopes on more coalition air power , which will likely increase as weather improves . `` We want more to bring a speedy end to this , '' Col. Ahmed Omar Bani , an opposition spokesman , told CNN . `` A strike is not a strike unless it kills , '' he said . CIA operatives have been in Libya working with rebel leaders to try to reverse gains by loyalist forces , a U.S. intelligence source said . The United States , insisting it is now fulfilling more of a support role in the coalition , shifted in that direction as NATO took sole command of air operations in Libya . The ferocity of this month 's fighting and Gadhafi 's advantage in firepower was clearly evident in Misrata , which has seen snipers , significant casualties and destruction . A witness told CNN Thursday there `` is utter madness '' and Gadhafi 's men are going door-to-door evicting and terrorizing people . `` I am afraid it will be one big massacre here in Misrata '' if the international forces `` do not do more , '' he said . CNN did not identify the witness for security reasons . Saddoun El-Misurati , a spokesman for the Libyan opposition in Misrata , described intense fighting and casualties in the city . `` We managed to get two shipments , so far , of badly needed medical supplies to the hospitals . But obviously we still need more supplies in dealing with the day-to-day casualties and the situation on the ground , '' he said . Gadhafi 's military capabilities had been steadily eroded since the onset of U.N.-sanctioned air strikes , U.S. officials have said . But the dictator 's forces outnumber the rebels by about 10-to-1 in terms of armor and other ground forces , Mullen noted . Defense Secretary Robert Gates , also speaking before the House committee , warned that the Libyan rebels still need significant training and assistance . `` It 's pretty much a pickup ballgame '' right now , he said . U.S. and British officials say no decision has been made about whether to arm the opposition . Dianne Feinstein , head of the Senate Intelligence Committee , told CNN 's `` The Situation Room '' she opposes doing that . The Democratic senator cited failures of such a move in other conflicts . Bani -- asked whether he is open to the idea of ground forces from outside Libya joining the rebels ' effort -- responded that `` all options are open to us . '' `` It has been very hard the past few days because the freedom forces have been facing heavy tanks and artillery weapons with very light weapons , '' the spokesman said . While some members of the Libyan military reportedly defected to join the opposition , the rebels include many volunteers who have not been trained . Over the weekend , CNN reported that rebels had taken al-Brega , Ras Lanuf and Bin Jawad , and reached a town just east of Sirte . But in the past three days , opposition fighters have been pushed back eastward . CNN 's Ben Wedeman , reporting Thursday from near al-Brega , said the rebels , armed with light mortars and machine guns , have displayed no strategy in their running battles with loyalist troops . Gates reiterated the Obama administration 's promise that no U.S. ground forces will be used in Libya , telling committee members that the rebels had indicated they did n't want such an intervention . But the United States does have CIA personnel on the ground . A U.S. intelligence source said the CIA is operating in the country to help increase U.S. `` military and political understanding '' of the situation . A former counterterrorism official with knowledge of U.S. Libya policy said there is a presidential finding authorizing the CIA to conduct operations in support of U.S. policy in Libya , including assessing the opposition and determining their needs . Specific activities by CIA officers will be determined by conditions on the ground and would need further approval from the White House , the source said . A former senior intelligence official said officers `` might be advising [ rebels ] on how to target the adversary , how to use the weapons they have , reconnaissance and counter-surveillance . '' Presidential findings are a type of secret order authorizing some covert intelligence operations . The CIA has had a presence in Libya for some time , a U.S. official told CNN earlier this month . `` The intelligence community is aggressively pursuing information on the ground , '' the official said . The CIA sent additional personnel to Libya to augment officers on the ground after the anti-government protests erupted , the official said , without giving details . CIA officers assisted with the rescue of one of two U.S. airmen whose fighter jet crashed in Libya on March 21 , a knowledgeable U.S. source said . NATO emphasized Thursday that the U.N. resolution authorizing action in Libya precludes `` occupation forces . '' NATO Adm. Giampaolo Di Paola , chairman of the NATO Military Committee , indicated that the presence of foreign intelligence personnel does not violate U.N. Security Council 1973 , which authorized action in Libya . Rebel forces have been demanding an end to Gadhafi 's nearly 42 years of rule in Libya . They have faced sustained attacks by a regime fighting to stay in power and portraying the opposition as terrorists backed by al Qaeda . Rebel forces have lost Bin Jawad and the key oil town of Ras Lanuf and are backed up to the al-Brega area , Bani said Wednesday . Ajdabiya , which is east of al-Brega , will be prepared as a `` defense point '' if the withdrawal continues farther east , he said . Amid the setbacks faced by rebels , a significant crack in Gadhafi 's armor surfaced when Libyan Foreign Minister Moussa Koussa fled to London on Wednesday and told the government there that he has resigned , the British Foreign Office said . Koussa -- a former head of Libyan intelligence -- was a stalwart defender of the government as recently as a month ago . But in recent weeks his demeanor had visibly changed . At one recent media briefing , he kept his head down as he read a statement and left early . British Foreign Secretary William Hague said Koussa had not been offered any immunity . Koussa 's defection provides evidence `` that Gadhafi 's regime ... is fragmented , under pressure and crumbling from within , '' said Hague , adding that Koussa is voluntarily speaking with officials in the United Kingdom . Libyan government spokesman Moussa Ibrahim said Thursday that Koussa did not tell the government he planned to resign before he flew to Britain . Ibrahim said Koussa asked for sick leave and the government gave him permission to leave the country and receive intensive medical care . The government had another setback Thursday , with news that an official who was picked as Libyan ambassador to the United Nations has defected . A relative and an opposition leader said Thursday that former Foreign Minister Ali Abdussalam Treki was in Cairo . CNN 's Nic Robertson , Ben Wedeman , Reza Sayah , Dana Bash , Pam Benson , Tim Lister and Zain Verjee contributed to this report .
Sen. Dianne Feinstein opposes arming the rebels . A witness said he fears a `` massacre '' in Misrata . A U.S. presidential finding authorizes CIA operations in Libya , a source says . White House : Libyan foreign minister 's defection shows pressure is `` having an effect ''