"We ... are opposed to carrying out illegal and immoral orders to attack, of the type Israel carries out in the territories," a letter from the pilots stated. "We ... refuse to continue to hit innocent civilians ...
"The continued occupation is critically harming the country's security" and moral fiber, the statement added.
While dozens of reservists in the ground forces have served jail time for refusing to serve in the West Bank and Gaza Strip, this is the first group of conscientious objectors in the air force — the pride of the Israeli military, reports CBS News Correspondent Robert Berger.
Meanwhile, Israeli troops backed by helicopters raided a refugee camp in the Gaza Strip, sparking a firefight with Palestinian gunmen. The army said two Islamic militants and an Israeli soldier were killed, and six Israeli soldiers wounded. A three-year-old Palestinian girl was also killed.
In the West Bank town of Hebron, Israeli troops stormed the hideout of two wanted Palestinian militants. Both were killed, including the local commander of the Islamic Jihad.
Pilots are held in the highest regard in Israel and their views carry considerable weight, since their skill and audacity are seen as key to Israel's survival.
Air Force commander Maj. Gen. Dan Halutz grounded nine of the pilots Thursday who are still on active duty, plus several flight instructors. If the active-duty pilots do not retract their statements in the next few days, they will be dismissed from active service.
Wednesday's signed declaration condemning the air strikes shook the nation and also raised new questions about the limits of protest in the military. Halutz said the signatories would be punished — possibly jailed — and accused them of playing politics, rather than grappling with genuine moral dilemmas.
"There is no corps and army more humane and moral than us," he said.
The group of 27 is informally led by Brig. Gen. Yiftah Spector, a highly decorated retired pilot who, according to Israeli media reports, participated in the bombing of the Iraqi nuclear reactor in 1982.
In their petition, the pilots said air strikes on crowded Palestinian areas are "illegal and immoral." They also condemn Israel's continued occupation of the West Bank and Gaza, saying it corrupts Israeli society.
In the past three years, some 140 Palestinian militants have been killed in targeted raids, according to Palestinian medical officials, though that also includes militants killed resisting arrest. They say more than 100 bystanders have also died.
The rebel pilots were lambasted Thursday in commentary in newspapers and radio talk shows. Critics accused the pilots of being immature, naive or having a secret political agenda.
Prime Minister Ariel Sharon was quoted as saying the protest was a "grave matter" and would be dealt with swiftly. Former Israeli President Ezer Weizman, who commanded the Israeli air force in the 1960s, said the pilots' stance was immoral and a disgrace, and belittled their apparent idealism as a "holier than thou attitude."
Halutz has ordered an investigation into the legality of the pilots wearing their uniforms during interviews they gave to Israeli television. If they were on reserve duty, they needed permission to talk to the media. If they were not, they were not allowed to wear their uniforms.
He played down the importance of the protest, saying the pilots were only a handful among thousands.
However, some warned the protest could spread because of growing unease in the armed forces over military strikes that have failed to stop terror attacks.
"Today, in light of pointless military operations ... people are beginning to ask questions," wrote military commentator Alex Fishman in the Yediot Ahronot daily. "And these (the pilots) are the very best people we have. We can ground them, and we can lock them up, but we cannot ignore the questions they ask."
Yediot said dozens of Apache helicopter pilots, who carry out the bulk of the air strikes, have met with their wing commander to express their concerns. One participant said he was not convinced of the justice of his missions, Yediot said, and others complained that they were given bad intelligence that could endanger civilians.
The rebel pilots could not be reached for comment Thursday, but Lt. Col. Zeev Rotem, a retired combat navigator speaking on their behalf, said the norms of the air force have changed in recent years.
"Today, we attack places where there are civilians, women and children, with the prior knowledge that ... there is a great chance they will be killed," Rotem told Israel Radio. The protest, he said, is a desperate attempt "to make the army, the government and the citizens ... stop this crazy cycle that has hijacked this country."
A watershed, for some pilots, apparently was last year's attack on Salah Shehadeh, leader of the Hamas military wing. A one-ton bomb killed Shehadeh, an assistant and also 14 civilians, nine of them children.
Halutz said at the time that he felt the bombing was morally correct.