The Taliban is waging an unusually aggressive campaign of violence in Afghanistan this winter, unleashing deadly bombings in the capital, threatening to overrun a strategic southern province, and attacking a foreign consulate.
Afghanistan's mountainous terrain and heavy snowfall have traditionally prompted a winter lull in fighting, with the militants using the colder months to rest and regroup ahead of an annual spring offensive.
There are several reasons why there has been no letup this winter, marking a seeming shift in the Taliban's decade-long insurgency.
The Taliban is trying to strengthen its negotiating hand amid a renewed international push to revive peace talks with the militant group, say analysts.
On January 11, Afghanistan and Pakistan are set to hold a first round of talks also involving the United States and China to try to agree a comprehensive road map for peace. Pakistan, which is said to wield considerable influence over the Taliban, hosted a breakthrough first round of talks in July.
"The surge in winter violence in Afghanistan appears to be timed with the pressure on Pakistan to induce the Taliban to join peace talks," Mohammad Taqi, a U.S.-based Pakistan political analyst, said.
"Pakistan seems to be betting on its Taliban proxy gaining a toehold such as in Helmand Province" -- where the Taliban is engaged in fierce fighting with Afghan and U.S. special forces after threatening to overturn several districts -- "and then to present that as a fait accompli to the Afghan government and the U.S."
Taqi added that whether or not the Taliban gains new territory, the violence will be used as leverage in talks.
The Washington Post last month quoted Western and Afghan officials as saying that "the Taliban now holds more [Afghan] territory than in any year since 2001," when the U.S.-led invasion ousted the Taliban regime that controlled much of the country.
Information gathered by the United Nations through October suggested UN security officials also rated the Taliban threat level as "high" or "extreme" in more Afghan administrative districts than at any time since 2001.
It is unclear whether the Taliban, which has previously maintained it will not hold talks with Kabul, will be represented in the Islamabad talks. Afghan officials have said they expect the militants to join the peace process at a later time.
"The Taliban keep themselves open to different scenarios," said Thomas Ruttig, co-director of the Afghanistan Analysts Network, an independent think tank in Kabul. "One, taking over the country again by military means. Second, if that's not possible, to get a part in government through talks. In both scenarios, making military gains helps."
Taliban leader Mullah Akhtar Mansur is trying to tighten his grip on power, and analysts say the high-profile attacks could boost his standing within the fractured group.
Mansur was declared the new Taliban leader in July after the Afghan government confirmed that Taliban spiritual leader Mullah Mohammad Omar had died in Pakistan in 2013. But a leadership tussle ensued and some Taliban commanders have refused to recognize Mansur. A breakaway Taliban faction has openly challenged the new leadership.
Mansur was seriously injured in a firefight at a meeting of Taliban militant commanders in neighboring Pakistan in December, exposing the divisions.
"Mullah Mansur wants to show that he is the leader and that he can do what Mullah Omar did," said Abdul Waheed Wafa, the director of the Afghanistan Center at Kabul University.
In fact, the Taliban now holds more territory in Afghanistan than in any period since the U.S.-led invasion in 2001 ousted it from power. As of November, about 7,000 members of the Afghan security forces had been killed this year, with 12,000 injured, a 26 percent increase over the total number of dead and wounded in all of 2014.
A number of new actors have entered the scene in Afghanistan recently, contributing to the surging violence as rival militant groups vie for territory and influence.
The breakaway Taliban faction, the High Council of the Islamic Emirate of Afghanistan, announced its arrival in November. Led by Mullah Mohammad Rasul, a former Taliban governor, the group has clashed with rival Taliban fighters for months.
Gunmen loyal to the Islamic State (IS) group are also increasing their footprint in Afghanistan, where they are attempting to establish a regional base. IS militants have been engaged in an escalating tit-for-tat war with government militias in eastern Afghanistan. Meanwhile, the Taliban's special forces have reportedly been deployed to hunt down the extremists.
"One of the factors for a very violent last six months has been the emergence of another Taliban group and also Daesh," said Wafa, using an Arabic phrase for IS. "There are a lot of reports from eastern Afghanistan of a bloody fight between the Taliban and Daesh."
There are also suspicions that elements within the Pakistani military establishment that have supported the Taliban are using the militants to attack Indian interests in Afghanistan and derail overtures from the Pakistani government toward New Delhi.
Pakistan and India recently agreed to relaunch peace talks, and Indian Prime Minister Narendra Modi made a surprise visit to Pakistan to meet Prime Minister Nawaz Sharif in December, the first by an Indian head of government in more than a decade, hours after visiting Kabul.
But analysts warned that two attacks on Indian interests recently -- a siege on the Indian consulate in the northern Afghan city of Mazar-e Sharif that ended on January 4 and a deadly assault on an air base in India -- could undermine peace efforts.
"The attack on the air base in Pathankot was timed to scuttle the Modi-Nawaz peace move," said Taqi. "It was calibrated to target a military facility and not unleash havoc like the 2008 Mumbai attacks," he said, referring to the coordinated bombings and shootings by a Pakistani-based militant group that killed more than 160 people and brought the archrivals to the brink of war.
"This recent attack throws a spanner in the talks and yet will not trigger a military response from India," Taqi added.
The latest attacks in India and Afghanistan have been linked to Pakistani militant outfits. The four gunmen who attacked the Indian consulate in Mazar-e Sharif are believed to be members of the banned Jaish-e-Mohammed militant group, which is based in Pakistan.
Before being killed, the gunmen wrote an Urdu-language message in their own blood stating that their goal was to avenge the killing of Afzal Guru, a member of the group who was hanged in 2013 for his role in the 2000 attack on the parliament building in New Delhi.