"Like the Soviets, we continue to secure and bolster a failing state, while encouraging an ideology and system of government unknown and unwanted by its people"
On Tuesday eight US soldiers and one Afghan civilian were killed in at least two bomb attacks in Kandahar province, taking the total US death toll for October to 55.
The attacks and Hoh's resignation are likely to step up pressure on Barack Obama, the US president, as he reviews military strategy in Afghanistan.
Plea to stay
The Washington Post said that Hoh's resignation had "sent ripples all the way to the White House".
Commenting on his departure, Ian Kelly, the White House spokesman, said that while Hoh was entitled to his views on the war, the US government would not change course.
"We take his point of view very seriously but we continue to believe that we are on track to achieving the goal that the president has set before us. That is ... improving Afghan governance, providing security, infrastructure, jobs - basically, giving the Afghan people an alternative to the very negative vision of the Taliban and al-Qaeda," Kelly said.
Government officials had tried to convince Hoh to stay, amid concerns that he could become a prominent voice against the US's involvement in Afghanistan, the Washington Post reported.
Hoh, a former Marine Corps captain and Iraq veteran, also turned down a senior staff-level job at the US embassy in Kabul after he resigned from his one-year contract position as a political officer in Zabul.
He was then called to Washington to meet Richard Holbrooke, the US special representative for Afghanistan and Pakistan.
"We took his letter very seriously, because he was a good officer," Holbrooke said in an interview with The Washington Post.
Hoh was initially convinced to stay by Holbrooke's insistence that he would be more effective inside government, but he changed his mind days later and once more handed in his resignation.
Speaking to the Washington Post, Hoh said that his resignation, which became final on Wednesday, was tendered because staying in his post "was not the right thing to do."
"I'm not some peacenik, pot-smoking hippie who wants everyone to be in love," he said.
Rosiland Jordan, Al Jazeera's correspondent in Washington, said that the content of the letter had won some endorsement.
"There is already support coming from liberal quarters [in the US] for what Matthew Hoh wrote in his resignation letter, which indicated that, in his view, the US has the wrong perception of who the enemy is inside Afghanistan," she said.
In his letter, Hoh said that many Afghans fight US forces because of their presence in the country and pointed to similarities with the Soviet Union's occupation of Afghanistan which ended with a humiliating withdrawal in 1989.
|The US commander in Afghanistan has called for 40,000 more troops [GALLO/GETTY]
"Like the Soviets, we continue to secure and bolster a failing state, while encouraging an ideology and system of government unknown and unwanted by its people," he wrote.
Hoh urged the Obama administration to reduce the number of US troops in Afghanistan, while calling for more support for neighbouring Pakistan in its fight against fighters allied to the Taliban and al-Qaeda.
"We want to have some kind of governance there, and we have some obligation for it not to be a bloodbath," Hoh told the Post.
"But you have to draw the line somewhere, and say this is their problem to solve."
Hoh's appeal for Obama to pull US troops out of Afghanistan is in contrast to the call by the senior commander of US and Nato forces in the country to send more soldiers.
General Stanley McChrystal is reported to have asked Obama for 40,000 more troops to be deployed to Afghanistan, to fight a war that the military commander says the US is currently at risk of losing.
Obama has said that he will not make a decision on troop numbers until a review of military strategy in Afghanistan is completed.