JALALABAD, Afghanistan (Reuters) - Security forces have “obliterated” Islamic State (IS) militants in Afghanistan, President Ashraf Ghani said on Tuesday, hours after a prisoner swap with Taliban insurgents raised hopes of a lull in violence in the country.

FILE PHOTO: Afghan presidential candidate Ashraf Ghani arrives to cast his vote in the presidential election in Kabul, Afghanistan September 28, 2019. REUTERS/Mohammad Ismail

More than 600 fighters from IS, locally known as Daesh, have surrendered with their families to the Afghan government in past weeks. Officials say air strikes by Afghan and coalition forces, lack of funds and low morale have forced the group to give up.

“No one believed one year ago that we would stand up and today be saying we have obliterated Daesh,” Ghani told a gathering of elders and officials in Jalalabad, the main city of eastern Nangarhar province that saw a wave of suicide attacks in past years claimed by the jihadists.

“Now that Daesh militants have surrendered, I ask authorities to treat their families humanely,” Ghani added.

The government says among fighters in its custody are foreign nationals from Pakistan, Tajikistan, Uzbekistan, Iran, Azerbaijan, Kazakhstan and the Maldives.

However, the Afghan Taliban, which has been battling IS and the government for control of the country, disputed that.

Zabihullah Mujahid, the Taliban’s official spokesman, described Ghani’s announcement as “absurd”.

“Kabul admin had 0% role in defeat of Daesh and the proud people of Nangarhar are witnesses,” he tweeted.

The Taliban controls more territory than at any point since the U.S. invasion in 2001, including sections of Nangarhar province.

Nangarhar, which shares a long and porous border with neighboring Pakistan, has long served as the main stronghold of IS, from where militants planned and staged bombings around the country, especially the capital Kabul.

Their attacks, targeting foreign nationals and the minority Shi’ite community, have killed hundreds.

Corroborating the government’s claims on defeating IS is difficult given the province’s remote and mountainous terrain, with diverse bands of fighters that often switch sides between militant groups and sometimes pro-government forces.

Last month, Washington announced that IS leader Abu Bakr al-Baghdadi killed himself during a raid by elite U.S. special operations forces in Syria.

The Taliban on Tuesday freed two Western professors in exchange for three of its senior leaders held by the government, in a rare act of cooperation between the warring sides.