ISLAMABAD - Pakistan’s unilateral fencing and construction of new observation posts on the long border with Afghanistan are “progressing smoothly” despite recent deadly clashes between the two countries and traditional terrain-related challenges.

The massive military-led effort to secure the 2,611-kilometer largely-porous frontier began in early 2017. Since then, a pair of 3-meter chain link fences, with a 2-meter gap topped with barbed wire, has been installed along more than 200 kilometers of the border, a senior security official working on the project told VOA Thursday.

The official said more than 150 new border posts and forts of 443 such planned facilities have been built, while the rest will be in place by 2019. He spoke on condition of anonymity because he was not authorized to share details on the ongoing project with media.

FILE - A view of the border fence outside the Kitt FILE - A view of the border fence outside the Kitton outpost on the border with Afghanistan in North Waziristan, Pakistan, Oct. 18, 2017. FILE - A view of the border fence outside the Kitton outpost on the border with Afghanistan in North Waziristan, Pakistan, Oct. 18, 2017.

Afghan authorities oppose the plan because they dispute the former British-era demarcation of 1893, maintaining that the barrier deepens problems for divided ethnic Pashtun families.

The Pakistani security official told VOA construction has been discussed and undertaken “in coordination with all parties, including the U.S. and Afghanistan."

Islamabad said its fortification plan, which will cost hundreds of millions of dollars, will stop militant infiltration and illegal crossings in both directions.

The border disagreements, however, have occasionally triggered skirmishes between Afghan and Pakistani forces. The latest such incident occurred this past Sunday (April 15) when, Pakistani officials say, a routine paramilitary patrolling and fencing action came under fire from the Afghan side in the Kurram border region.

“The Afghan border security forces, assisted by Afghan tribesmen, fired on our troops, resulting in shahadat [martyrdom] of five soldiers,” Foreign Ministry spokesman Mohammad Faisal said at Thursday’s weekly news conference.

“A border flag meeting was held between the commanders of the two forces and the situation was amicably defused...In their engagement, the two sides emphasized the need for further enhancing border coordination to avoid a recurrence of such incidents in the future,” said Faisal.

Afghan officials also reported fatalities on their side.

Speaking to VOA, the Pakistani security official said the border clash is “proof the Pakistani army is eager to plug the gaps as early as possible to secure the western border. Neither the military tensions nor the terrain and weather-related challenges has "in any way slowed down” the pace of the fencing project," he said.

“A stable western border is in the interest of Pakistan and synchronized efforts are in hand on a fast track basis to complete this daunting mission because it is vital for the security of Pakistan and it will also end the blame game,” the official said.

FILE - A sniper and spotter look out over the bord A sniper and spotter look out over the border in the Kitton outpost along the border fence on the border with Afghanistan in North Waziristan, Pakistan, Oct. 18, 2017. A sniper and spotter look out over the border in the Kitton outpost along the border fence on the border with Afghanistan in North Waziristan, Pakistan, Oct. 18, 2017.

Afghan and U.S. officials have long alleged that Taliban insurgents use sanctuaries on Pakistani soil to plot and sustain cross-border attacks. Islamabad rejects the accusations and says its security forces eliminated all militant groups from their territory before undertaking the Afghan border security project to ensure long-running regional security and stability.

Pakistani officials allege that after having fled security operations, militants have taken refuge in border areas of Afghanistan and are plotting terrorist attacks against Pakistan from there.