The United States says the decision to suspend talks with Russia over Syria was not taken lightly.
Plans to jointly target the self-proclaimed Islamic State and similar militant groups in Syria have been dropped following Russia's military role in the assault on the besieged city of Aleppo.
The decision reflects the highly aggravated tensions between the two powers.
The US State Department's Elizabeth Trudeau says the United States did all it could to work together and target groups like IS, also known as Daesh.
"The United States spared no effort in negotiating, in attempting to implement, an arrangement with Russia aimed at reducing violence, providing unhindered humanitarian access and degrading terrorist organisations operating in Syria, including Daesh and al-Qaeda in Syria."
Confirmation that talks between the two countries have collapsed suggests there is little hope of finding a diplomatic solution to Syria's civil war anytime soon.
It could also trigger deeper US consideration of military options, including training Syrian rebel groups and providing more sophisticated arms.
The United States says it will continue to communicate with the Russian military to avoid accidental military interactions in Syria.
But Ms Trudeau says Russia's actions in the weeks since the latest ceasefire was brokered have violated international laws and a United Nations Security Council resolution
"Unfortunately, Russia failed to live up to its own commitments, including its obligations under international humanitarian law and UN SCR 2254."
The worsening bilateral relations have been further amplified by Russian president Vladimir Putin accusing the United States of what he calls "unfriendly actions" towards Russia.
President Putin has suspended an agreement between the two countries on the disposal of surplus weapons-grade plutonium.
The deal, struck in 2000, is meant to result in both sides getting rid of 34 tonnes of plutonium by burning it in reactors.
Russian military analyst Pavel Podvig has told Al Jazeera television parts of the deal will still be upheld but the suspension of talks signals a backwards step.
"The importance of this particular agreement was not as much in the amount of material that is disposed of but mostly in the infrastructure that this agreement built for future progress in reducing nuclear weapons, in eliminating fissile materials and doing so in a verifiable and transparent way. Now that process is in danger, I would say."
Russia's bombing campaign in Syria has escalated in recent weeks, with some describing it as a war crime.
But Russia's ambassador to the United Nations, Vitaly Churkin, says the Syrian government is not always aware it is targeting hospitals.
"They say they are concerned that they will be bombed by the government. They're not identified as hospitals. So something is bombed which is used as a hospital, maybe has been used as a hospital for four years, but, officially, the Syrian government has no idea that this is a hospital."
The United Nations is negotiating a draft resolution urging Russia and the United States to ensure an immediate truce in Aleppo.
UN Secretary-General Ban Ki-moon says the carnage in Aleppo needs to end.
"We are out of words to express our outrage at the carnage, especially in Aleppo. The brutality is unrelenting. I strongly condemn the deliberate campaign against civilians and the health workers and humanitarian personnel trying to save them. The parties have first obligation. Countries with influence are also responsible for ending the attacks."
But White House spokesman Josh Earnest says there are clear difficulties in reaching such a resolution.
"What's clear is that there's nothing more for the United States and Russia to talk about, with regards to trying to reach an agreement that would reduce the violence inside of Syria. And that's tragic. And you're right that it's likely to lead that ongoing Russian violence aiding and abetting Assad regime forces means that there are likely more Syrian people who are going to get killed, innocent Syrian civilians."
