Myanmar's leader and Nobel Peace laureate Aung San Suu Kyi will head a delegation to the United Nations' top court to argue against a case accusing the mainly Buddhist country of genocide against the Rohingya, the government said.
More than 730,000 Rohingya, most of them Muslims, fled to neighbouring Bangladesh following a 2017 crackdown by Myanmar's military, which UN investigators said was carried out with "genocidal intent".
Myanmar has repeatedly justified the crackdown on the Rohingya as necessary to stamp out "terrorism". It also insists its own committees are adequate to investigate allegations of abuse.
The Gambia, a tiny mainly-Muslim West African nation, lodged its lawsuit after winning the support of the Organisation for Islamic Cooperation (OIC), which has 57 member states.
Only a state can file a case against another state at the International Court of Justice (ICJ).
The case will be the first international legal attempt to bring Myanmar to justice over the Rohingya crisis, and is a rare example of a country suing another over an issue to which it is not directly a party.
The ICJ has said it will hold the first public hearings in the case from December 10-12.
An 'historic' moment for Rohingya
A spokesman for Suu Kyi 's party, the National League for Democracy, said she had decided to front the delegation as allegations had been made against her personally.
"They accused that Daw Aung San Suu Kyi didn't speak out about violations against human rights," spokesman Myo Nyunt said.
"And they accused that she didn't try to stop human rights violations. She decided to face that lawsuit by herself."
Suu Kyi's office said in a Facebook post that Myanmar had retained "prominent international lawyers" to contest the case.
"The State Counselor, in her capacity as Union Minister for Foreign Affairs, will lead a team to the Hague in the Netherlands to defend the national interest of Myanmar at the ICJ," it said, giving no further details.
Rohingya activists celebrated the announcement of the ICJ case, with Nay San Lwin, campaign coordinator of the Free Rohingya coalition, telling Al Jazeera it was "historic".
"We have been victims of an ongoing genocide since 1978. We have been expecting justice [for a] very long time. I find no words to express my happiness,"
Nay added that a ruling from the ICJ could be a first step to returning rights stripped from the Rohingya.
"We have been driven out of our land, we want to live back in our homeland in Arakan or Rakhine state with human dignity, full citizenship and equal rights as other people [have] across Myanmar.
"We demand compensation, we need protection to prevent further attacks on us. All these can be gained through the ICJ and [it] must take this case to the UN Security Council and get a referral for the International Criminal Court (ICC) so all perpetrators will be punished," Nay told Al Jazeera.
The Gambia and Myanmar are signatories to the 1948 Genocide Convention, which not only prohibits states from committing genocide but also compels all signatory states to prevent and punish the crime of genocide.
Akila Radhakrishnan, president of the Global Justice Center, noted that Myanmar's civilian government had failed to act in 2017 and taken no steps to hold the military to account.
"Now, they are going to defend the military and the government's genocidal actions on one of the world's largest and most influential stages," Radhakrishnan said in a statement.
"The international community should no longer have illusions where Suu Kyi and the civilian government stand and must act to support The Gambia and take other measures to hold Myanmar accountable."
The ICJ was set up in 1946 after the Second World War to adjudicate in disputes between UN member states.
The ICC - another Hague-based court - was set up in 2002 to probe war crimes, Last week it authorised its chief prosecutor to launch a full investigation into the persecution of the Rohingya. A separate criminal complaint was filed in Argentina naming Suu Kyi.
Myanmar has rejected the ICC probe and a spokesman for Suu Kyi's party called the Argentine case a "violation of Myanmar's sovereignty".
Charlotte Mitchell contributed to this report: @charbrowmitch