MAZAR I SHARIF, Afghanistan — Violence in northern Afghanistan has intensified in recent days, with both Afghan security forces and the Taliban suffering heavy casualties, but the heavy fighting has failed to shift the battle lines in the 17-year-old war.
While many previous winters brought a relative lull to the war, as low temperatures and snow set in, this year the fighting has continued amid stalled efforts to persuade the Taliban to sit down for talks with the Afghan government.
Despite meeting repeatedly with American diplomats to discuss the withdrawal of United States forces from Afghanistan and the release of their prisoners, the insurgents have refused to meet Afghan peace negotiators.
Instead, the Taliban have carried out deadly attacks in Balkh Province, a commercial hub in the north that had long remained one of the safest parts of the country, and in several neighboring provinces.
Some of the attacks have occurred along major highways, restricting movement and in some areas blocking the highway connecting the provinces to one another and to the capital, Kabul.
In the past 24 hours, the Taliban have killed more than 30 police officers and soldiers in the north alone.
In return, the American and Afghan Air Forces have unleashed deadly airstrikes, often resulting in large numbers of Taliban casualties.
Nisar Ahmad Ghoryani, the head of the Afghan Parliament’s security and defense commission, accused the Taliban of using the violence to gain leverage before sitting down for any talks.
He also accused Pakistan and to some extent Russia — which the United States military has claimed works surreptitiously with the Taliban — of increasing their support for the insurgents even as Islamabad and Moscow have made gestures toward achieving peace talks.
“The Taliban, with help of Russia and Pakistan, are trying to get more territory and to be in a stronger position in the war so they can get more in a peace deal,” Mr. Ghoryani said.
Despite the ferocity of the fighting and the high death toll, the battle lines are not shifting significantly, he said.
“A group of 50 or 60 Taliban fighters attack a security outpost in the middle of the night, they kill most of those in the post with snipers from far away — they can’t fight face to face during the day,” Mr. Ghoryani said.
“The Taliban have also suffered heavy casualties in recent weeks,” he added, “but they can still carry out attacks, because they get enough military and financial support.”
While the Afghan forces have lost fighters in record numbers, Afghan and Western officials say that one recent sign of optimism has been a change of leadership in the country’s army and police force.
New interior and defense ministers, both of whom are veterans of the 17-year-old war, have promised to reinvigorate a military that President Ashraf Ghani says has lost more than 28,000 members since 2015. Other officials say the loss is probably even higher, with the police force alone losing 19,000 members in the past four years.
Taliban attacks have also affected the country’s western Herat and Badghis Provinces in recent days, killing at least 19 members of the Afghan security forces and wounding 26 others, officials said. The insurgents also suffered heavy casualties, officials said.
The Islamic State is at the center of the violence in the eastern Afghanistan, where it has gained a foothold. Officials said the local chapter of the terrorist group had pushed back the Taliban from the Korengal Valley in Kunar Province, which the American military left years ago after heavy casualties.
“Daesh took complete control of the Korengal valley,” said Abdul Latif Fazly, a member of Kunar provincial council, referring to the militant group by its Arabic name.
Mr. Fazly said hundreds of Islamic State fighters had gathered from Kunar, as well as neighboring Nangarhar, where its presence is strongest, to attack the valley and push back the Taliban.
While officials long said that the group had been contained after concerted military operations, and that its size in Afghanistan had shrunk, the takeover of the valley has raised concerns among residents in eastern Afghanistan.
If the group consolidates its hold in the valley, it would threaten several neighboring districts as well as the main road leading to neighboring Nuristan Province.