The expelled officials included some of the brightest rising stars in President Xi Jinping’s military: two generals who oversaw satellite launches and manned space missions, an admiral who helped entrench Beijing’s presence in the disputed South China Sea, and a missile commander who had honed China’s ability to respond to a possible nuclear war.

They were among nine high-ranking Chinese military figures who were recently removed as delegates to the country’s Communist Party-run legislature, abruptly and without official explanation.

Experts say the move indicates that Xi’s latest offensive to root out alleged corruption and other misconduct in the People’s Liberation Army has been gaining momentum and is focused on the politically sensitive agencies responsible for developing weapons and military installations.

In October, China suddenly dismissed the defense minister, who had worked for years in the military’s arms acquisition system. Months earlier, two commanders of the Rocket Force, which controls China’s nuclear missiles, were replaced.

Since coming to power in 2012, Xi has launched scorching, high-decibel crackdowns on Communist Party officials and generals. This latest campaign in the military, however, has been conducted mostly on the quiet, with no official acknowledgment that it is even underway.

Experts who track China’s military said Xi’s strategy appeared to be a surgical attack designed to assert his control over the arms sector. They noted that dismissals apparently excluded long-standing allies of Xi, at least for now.

The pattern suggested a “targeted crackdown” that “serves notice that even in the most critical technological sectors, the party is willing to crack down to ensure the long-term healthy development of these sectors,” said Tai Ming Cheung, a professor at the University of California, San Diego who has long studied China’s weapons development programs.

Tai noted that China’s arms development programs are some of the “most secretive” aspects of its military, into which vast funds have been poured over the past several decades. “It is ripe for corruption on a grand scale,” he wrote in an email.

China announced the dismissals from the legislature, called the National People’s Congress, in a terse statement Dec. 29. Two days earlier, the Chinese People’s Political Consultative Conference — a top political advisory body — said it had expelled three executives from military-related state-owned companies: one from the China North Industries Group Corp, or Norinco, a weapons conglomerate; and the others from the China Aerospace Science and Technology Corp.

The anti-corruption drive may tarnish Xi’s image of political invulnerability, because the officers who have been removed all owed their advancement to him.

On the other hand, Xi’s bold moves against serving military officers are a sign that he retains unrivaled control despite China’s economic woes, said Christopher Johnson, a former CIA analyst of Chinese politics.

“Xi’s willingness to take on the embarrassment of such a massive purge shows how determined he is to ensure that his military can carry out his mandate to ‘fight and win wars,’ ” Johnson said.

Not long after Xi came to power, he launched a crackdown on graft in the military, warning that such abuses would endanger China’s security as the country’s rivalry with the West intensified. Dozens of commanders and generals were convicted of corruption in the form of selling military assets, contracts or promotions.

But at the time, he was still consolidating his power as China’s leader, and that crackdown focused mostly on retired officials.

“Now, his power is sufficiently incontestable that he can go at the roots of the problem with relative abandon,” Johnson said.

Military investigators “have long identified armament procurement as one of the top areas for corruption in the PLA,” according to Tai.

But in earlier anti-corruption campaigns, few of the officials known to have been arrested had worked in this sector. “This time around, the weapons acquisition and defense industries appear to be among the prime areas to be targeted,” he said.

The first visible signs of the crackdown were the removal last year of the two rocket force commanders, followed by Gen. Li Shangfu, the defense minister. It’s possible that problems found in the rocket force have snowballed into a broader investigation, experts say.

Some of the officers ousted in recent days had crossed paths with Li when he was in the General Armaments Department, which oversaw procurement, or the agency that succeeded it after Xi moved to reorganize the military in 2015. But others did not, suggesting that the investigations extend beyond Li’s circle, said Yao Cheng, a former Chinese naval officer now living in the United States.