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In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.

ISLAMABAD, Pakistan—Pakistan said it has begun building a fence along its border with Afghanistan, a move that could further rile relations between the two countries, each of which blames the other for harboring terrorists. 
  
 Kabul doesn’t recognize hundreds of miles of Pakistan’s mountainous northwest border, which was drawn up under British colonial rule. Pakistan in February closed the border for “security reasons” for more than a month, to protests from landlocked Afghanistan, reopening it on March 20. 
  
 ... ||||| FILE - In this June 15, 2016 file photo, a Pakistani army soldier stands guard in Pakistani tribal area of Khyber, near Torkham border post between Pakistan and Afghanistan. Pakistan started building... (Associated Press) 
  
 FILE - In this June 15, 2016 file photo, a Pakistani army soldier stands guard in Pakistani tribal area of Khyber, near Torkham border post between Pakistan and Afghanistan. Pakistan started building a fence along the Afghan border in areas where it says militants have launched cross-border attacks... (Associated Press) 
  
 FILE - In this June 15, 2016 file photo, a Pakistani army soldier stands guard in Pakistani tribal area of Khyber, near Torkham border post between Pakistan and Afghanistan. Pakistan started building a fence along the Afghan border in areas where it says militants have launched cross-border attacks... (Associated Press) FILE - In this June 15, 2016 file photo, a Pakistani army soldier stands guard in Pakistani tribal area of Khyber, near Torkham border post between Pakistan and Afghanistan. Pakistan started building... (Associated Press) 
  
 ISLAMABAD (AP) — Pakistan says it has started building a fence along the Afghan border in areas where it says militants have launched cross-border attacks, a move that could worsen tensions with Afghanistan, which has never accepted the colonial-era frontier. 
  
 Gen. Qamar Javed Bajwa, the head of Pakistan's armed forces, announced the construction of fencing in "high threat zones" Saturday during a visit to tribal regions along the border, saying it was in the interest of both countries. 
  
 The two countries share a 2,400-kilometer (1,500-mile) internationally recognized border known as the Durand Line, which was drawn in the 19th century, when the British dominated South Asia. 
  
 The Afghan government has never recognized the border, which runs through the Pashtun heartland, diluting the power of Afghanistan's largest ethnic group on both sides. 
  
 Najib Danish, the deputy spokesman for the Afghan Interior Ministry, said authorities had not yet seen any signs of construction along the frontier but would move to prevent any such project. 
  
 "Building fences or any construction is not acceptable for us and we won't allow anyone to do it," he said. 
  
 Pakistan and Afghanistan have long accused each other of turning a blind eye to Islamic militants operating along the porous frontier, and Pakistan recently closed the border for more than a month 
  
 Bajwa said Pakistan is trying to develop a bilateral border security mechanism with Afghanistan. 
  
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 Associated Press reporter Rahim Faiez in Kabul, Afghanistan contributed to this report. |||||
Output:
Pakistan has started building a barrier along parts of one of the most rugged and dangerous border regions in the world: the 1,510-mile border with Afghanistan, which cuts the heartland of the Pashtun ethnic group in two. Pakistan says Taliban militants have been launching attacks across the border, a colonial-era boundary that Afghanistan has never officially recognized, the AP reports. Pakistan Army chief Gen. Qamar Bajwa visited tribal areas along the border Saturday and said construction of a fence is underway in some high-risk areas. A secure border is "in the "mutual interest of both brotherly countries who have given phenomenal sacrifices in war against terrorism," the general said. Afghanistan, in turn, accuses Pakistan of sheltering militants from the Pashtun-dominated Taliban, but says building a fence is not the answer, the Wall Street Journal reports. "Pakistan needs to deny sanctuaries to terrorist groups, stop financing, training and helping them … that's something that would help stop terrorist attacks," said Afghan defense ministry spokesman Gen. Dawlat Waziri. Pakistan, which is building the fence in a tribal area where the country's laws don't fully apply, has already dug a trench hundreds of miles long along another section of the border with Afghanistan. The Financial Times notes that the number of border walls worldwide has surged to more than 70 in the years since 9/11.