Here is what you need to know about the matter:

1. Who lodged the complaint?
The case was lodged on December 27/12/2019 in the US District Court for Columbia by a group of US law firms on behalf of 385 Americans, including the families of US servicemen killed or wounded in Afghanistan by the Taliban and al-Qaeda between 2009 and 2017. Court documents name over 100 killed or injured US servicemen, or their family members, as plaintiffs.

2. Since when has MTN been doing business in Afghanistan?
MTN's Afghan subsidiary MTN Afghanistan has been operating in the country since 2006 when MTN bought Areeba - a Lebanese telecoms company that won a licence to provide cellphone services. When MTN entered the market, it was the third-largest cellular-service provider. By 2010 it held the greatest market share - 32% - of Afghanistan's four cellular phone providers, according to the court filings.
"By 2012, MTN had a presence in virtually every province in Afghanistan, including many that were under Taliban control or influence," the documents read.
According to its 2018 Annual Report, MTN had 6.4 million Afghan subscribers at the end of 2018.

3. What is MTN being accused of?
MTN is among several multinational businesses named in the lawsuit for allegedly supporting or aiding the Taliban by making protection payments. According to the plaintiffs' court filings, the defendants paid off the Taliban so that their business interests would not be attacked.
"Those protection payments aided and abetted terrorism by directly funding an al-Qaeda-backed Taliban insurgency that killed and injured thousands of Americans."
"The payments saved defendants money: it was cheaper to buy off the Taliban than it would have been to invest in the security necessary to mitigate the terrorists' threats," the plaintiffs allege.
According to the plaintiffs, MTN made protection payments to the Taliban from 2006 when it entered the market. Referencing newspaper articles, the lawsuit states that the protection payments were in the region of $2 000 per cell tower per month. The plaintiffs say the mobile operator has around 1 300 cellphone towers in the country.
The lawsuit claims that the Taliban made payment demands via so-called 'Night Letters' which it sent to mobile phone operators.
"MTN was a particularly aggressive practitioner of protection payments. Rather than invest in expensive security for its transmission masts, MTN purchased security by buying it from the Taliban."
The plaintiffs further allege that not only did MTN make protection payments, but it also on occasion deactivated its cellular networks at night at the request of the Taliban.

4. What would be the impact of shutting off cellphone towers?
According to the plaintiffs' filings, MTN allegedly switched off cellphone towers at the request of the Taliban, which undermined the counter-insurgency efforts of the US.
"By 2010, the Taliban was 'using the cellphone system as an instrument of war against the Afghan government and the US-led coalition,'" the suit states.
The plaintiffs argue that while the Taliban relied on cell phones for communication and to coordinate attacks, US intelligence could track phone signals and detect attacks.
Deactivating cellular networks made it difficult for the US intelligence to track insurgents.
"By agreeing to shut down its transmission masts, MTN knowingly deprived coalition forces of that vital intelligence," the plaintiffs allege.

5. What has MTN's response been?
In a shareholder notice on Monday morning, MTN said it is reviewing the details of the report and consulting with its advisers. It added it remains of the view that it conducts its business in a responsible and compliant manner in all its territories it operates and intends to defend its position "where necessary".
The group said it would not be issuing further comment on the matter at this stage.

6. What are the plaintiffs asking for?
The plaintiffs want the court to find the defendants liable under the anti-terrorism act.
Furthermore, the lawsuit seeks damages under the US anti-terrorism act, on behalf of the American service members, civilians and their families who were killed or wounded while serving the US, in Afghanistan.