The two journalists that are awaiting trial, Loic Lawson, the director of the Flambeau des Democrates newspaper, and Anani Sossou, an independent journalist, are known for their critical positions against the regime of President Faure Gnassingbe.
Through a report released Tuesday, RSF said “at least 23 spyware intrusions between 1 February and 10 July 2021 were identified on one of the phones used by Loic Lawson.”
"Freelance journalist Anani Sossou was the target of a similar attack on his phone a few months later, on 25 October 2021," the media advocacy group added.
RSF said the intrusion used Pegasus, a spyware made by Israel's NSO Group. Togo has been accused in the past of using it against dissidents.
The Togolese government did not immediately respond to an AFP request for comment.
RSF said Togolese Communication Minister and government spokesperson Yawa Kouigan did not respond to its request for an explanation of the surveillance operation targeting journalists and the use of such methods in the West African nation.
The media advocacy group began its investigation in December, when the two journalists were released after 18 days of detention for "defamation" against Minister of Urban Planning, Housing and Land Reform Kodjo Adedze.
The journalists had claimed on social networks that the minister had 400 million West African CFA francs ($659,000) stolen from his home.
They then went back on their assertion, saying that "extensive investigations" had shown the amount was overestimated.
But the minister, who had declared a burglary to the police without the amount being made public, filed a complaint against the journalists.
Their trial opened on Jan. 17, but the court declared itself incompetent to judge the case and referred them to the Court of Appeal.
It is not the first time that Togo has been singled out for its use of Pegasus.
In August 2020, an investigation by French daily Le Monde and Britain's The Guardian revealed that Pegasus "sold in the United States by the Israeli company NSO, was used against voices critical of the regime" of Gnassingbe, including opponents, civil society activists and Catholic clerics.
Gnassingbe has been in power since 2005 after succeeding his father, General Gnassingbe Eyadema, who ruled with an iron fist for 38 years.