At least 100 officers from an elite unit in the Israeli Air Force have threatened to stop working if the government goes ahead with a judicial overhaul plan which has triggered a deep political and constitutional crisis in Israel.
"The call of our conscience may determine that we can no longer report to reserve duty," the officers wrote in a joint letter, published by Israeli media on Thursday night.
"In face of the constitutional situation developing in front of our eyes, which includes the demise of Israeli democracy as we know it, we fear that following military orders would be a violation of our oath, our conscience, and our mission."
A former commander of the elite air force unit told Israel's Channel 12 that the country was witnessing "the greatest threat" from within.
"This is a small unit. We never thought in our wildest nightmares that the greatest threat to Israel's survival as a Jewish and democratic country will be internal rather than an external enemy. Now that it is happening, we are determined to prevent it," he said.
He said he believed that the officers would rebel against the "undemocratic regime" if the legal package is fully approved and implemented.
Rights activists have pointed out the continued repression of Palestinians inside Israel and in the occupied West Bank, but say the judicial overhaul will likely worsen their already grim situation.
Israel's air force, meanwhile, has killed thousands of civilians in the bombing of besieged Gaza.
Hundreds of other reservists from Israel's military, police, and intelligence have also announced that they will not report to duty to protest the planned changes to the judiciary.
Israelis believe the plans will see all legislative powers handed to Prime Minister Benjamin Netanyahu's government.
A bill limiting the Supreme Court's ability to overturn laws it deems unconstitutional was approved at its first reading by the Knesset earlier this week.
It is a key element of the judicial overhaul package that has fuelled many weeks of protests, who say the plan undermines judicial independence and "Israeli democracy".
Netanyahu and Justice Minister Yariv Levin argue that the changes are necessary to reset the balance between elected officials and the Supreme Court. The reforms would also grant the ruling coalition more powers in appointing judges.
Netanyahu has rejected a compromise plan touted by the country's president, who warned of Israel slipping into civil war.
President Isaac Herzog - who holds a largely ceremonial role - presented a proposed compromise on the reforms on Wednesday, but it was immediately rejected by Netanyahu’s hard-line government.
Former Israeli Prime Minister Ehud Olmert called on world leaders to boycott Netanyahu over the plans.
Olmert told Channel 12 that Netanyahu should have accepted Herzog's proposal.
"All prime ministers who define themselves as friends of Israel need to come out against the government. The government is anti-Israel," he said.
Olmert - who headed Israel’s government during the 2006 bloody war on Lebanon - said he believed Netanyahu would have accepted Herzog's proposals but was pressured to back down by Levin.