India is expected to evacuate up to 150 people, including its own nationals and dozens of Afghan Sikhs and Hindus, from Kabul to Dushanbe in military aircraft on Monday before flying them home on commercial flights.

A group of almost 50 Afghan Sikhs and Hindus entered Kabul airport by Monday afternoon, hours after an Afghan soldier was killed and three more were injured in a gun battle near the military side of the facility. The firefight began when a sniper outside the airport fired at former Afghan soldiers helping US forces as guards.

The Indian side is hopeful of pulling out almost all of the Indian nationals who have registered for evacuation flights by Monday, along with Afghan Sikhs and Hindus and other Afghan citizens, people familiar with developments said on condition of anonymity.

C-130 aircraft of the Indian Air Force (IAF) will fly the people to the Tajikistan capital of Dushanbe, from where they will be brought home in Air India flights.

On Sunday, India evacuated nearly 540 people, including 475 of its nationals, on several flights from Kabul, Dushanbe and Doha. Nearly 200 people – including diplomats, officials and security personnel posted at the Indian embassy and some Indian nationals – were flown out of Kabul within two days of the Taliban marching into the Afghan capital.

The people cited above said Dushanbe had emerged as an important hub for the evacuation flights for a variety of reasons, including logistics and support infrastructure.

“Time slots and space at Kabul airport continue to be limited. It is easier to station our aircraft in Tajikistan and fly the evacuees from Kabul to Dushanbe whenever we have gathered enough people at the airport. The flight takes about 45 minutes,” one of the people said.

“It is also easier to process all the paperwork and complete all the formalities for the evacuees in Dushanbe, where we have back up from the Indian embassy. Plus, we have access to the airbase at Ayni near Dushanbe,” the person said.

“Besides, the evacuees get some time to rest and recover after the harrowing journey into Kabul airport, which remains the most difficult part of the evacuation process,” the person added.

Since 2002, India has renovated the Ayni airbase, located 10 km west of Dushanbe, at a cost of more than $70 million under an agreement with Tajikistan. The upgrades included extending the runway to 3,200 metres and installing navigation and defensive equipment.

The tactic of flying the evacuees from Kabul to Dushanbe and then sending them back home in commercial flights has proved to be less time-consuming, the people said. The Air India aircraft can fly directly from Dushanbe to New Delhi via Pakistani airspace, unlike military aircraft which have to take a longer route through Iranian airspace and over the Arabian Sea.

Some of the airlifts using the IAF’s C-17 Globemaster heavy lift aircraft had involved the more circuitous route and more stops for refuelling, the people pointed out.

The security situation at Kabul airport, which is controlled by the US military, continues to be precarious. At least 20 people have died in the chaos at the airport, mostly in shootings and stampedes, as US and international forces try to evacuate citizens and Afghans facing threats from the Taliban.

The Taliban have deployed hundreds of their fighters outside the airport to enforce some sort of order. On Saturday, seven Afghans were killed in a crush at the gates.

The gun battle near the north gate of the Kabul airport on Monday, which also involved US and German troops, highlighted the fragile security situation in the area.

President Joe Biden said on Sunday the US could extend the August 31 deadline for the withdrawal of American forces from Afghanistan in order to fly out thousands of US citizens and Afghans, but Taliban spokesman Suhail Shaheen described the development as a “red line” and warned that there “would be consequences” if the US or the UK were to seek additional time for evacuations.

UK Prime Minister Boris Johnson is expected to urge Biden this week to extend the evacuation deadline.