Tom Amenta, a Chicago native who enlisted in the US military against his family’s wishes, said he found himself in the “middle of nowhere,” Afghanistan, in 2002 as an Army ranger in a remote area 15 minutes from the Pakistani border. He was fighting the opening battles of a war that few expected to last 20 years.

He was 40 years old and retired from the military when he watched the evening news on Thursday while on a business trip to Pennsylvania.

Headline after headline reported on Taliban fighters’ latest gains, which have taken control of more than a dozen of the country’s provincial capitals as the Afghan government approaches collapse in the final days of the US withdrawal. News of suspected war crimes committed by fighters against civilians or Afghan troops riveted him in horror.

Friends who had been killed there, including NFL star Pat Tillman, came to mind. Former Afghan colleagues, such as interpreters, who remained in the country and whose fates he didn’t know, also resurfaced in his mind.

“It makes me really angry,” Amenta said of the US withdrawal, lamenting the billions of dollars spent on the war effort. Not to mention the emotional, financial, and human costs borne by thousands of Americans who served or had loved ones sent to fight in Afghanistan.

Amenta is one of many veterans around the world who are frustrated by the Taliban’s faster-than-expected resurgence, demonstrating how deeply the conflict resonates around the world. Approximately four dozen countries have sent troops to support the United States, which has spilled the most blood in the war, excluding Afghanistan, with 2,300 killed while serving. Jay A. Blessing of Tacoma, Wash., a goofy friend and fellow Army ranger who used to put hot sauce on everything: “I mean, literally everything,” Amenta said. He slathered hot sauce on his ice cream.” Blessing was killed by an improvised bomb in Asadabad, Afghanistan, in 2003.

In the United Kingdom, where at least 455 British lives have been lost during the war, Foreign Affairs Select Committee Chair Tom Tugendhat, who served in Afghanistan, tweeted: “If you think I’m taking the news from Afghanistan badly and personally, you’re right.”

Tugendhat called the withdrawal “wasteful and unnecessary.” “I’ve seen what it costs and what sacrifices are made,” he said.

Tugendhat claimed that the country’s government had become exposed and weak as a result of the withdrawal of coalition support. “We’ve yanked the rug out from under them,” he declared. “We’ve taken away their air support and logistics, and we’ve said, ‘Go on then, let’s see how you do.’

Army veteran John Whalen sighed from his Tucson home as news came in that Kandahar, Afghanistan’s second-largest city, had fallen to the Taliban. In 2010, Whalen’s friends Andrew Meari of Plainfield, Ill., and Jonathan Curtis of Belmont, Mass., were killed just a dozen miles from Kandahar.

The two were stationed at Combat Outpost Sanjaray, guarding an entry point. According to the Associated Press, when they stopped a suspicious individual from entering the base, the individual detonated the explosives he had wired on himself.

Former Army medic Frank Scott Novak, 44, said he has repeatedly heard from military friends who served in Afghanistan about a lingering sense of sadness as events unfolded. From 2004 to 2006, Novak served two tours in Iraq. Michelle Partington, the first woman to serve as a front-line Royal Air Force paramedic, told Britain’s Channel 4 that witnessing the country’s decline is unbearable.

Partington has post-traumatic stress disorder as a result of three deployments to Afghanistan, which she described as a “nightmare,” citing bomb blasts, injuries, and widespread destruction. She told the broadcaster that upon her return from the country, she often considered suicide.

On his way home from work on a Friday night in Seoul, retired South Korean army colonel Jeong Jangsoo expressed a range of emotions, none of which were positive, after learning that the Taliban was closing in on Kabul.

Jeong commanded an approximate 300-person South Korean contingent in Afghanistan in 2007, when the Taliban had kidnapped a South Korean Christian group, ultimately killing two of them.