After probes in nine states and twelve issued warrants, Brazilian police have arrested ten suspects, including one minor, for plotting jihadist attacks on the upcoming 2016 Summer Olympics in Rio de Janeiro.

Police expert to arrest the two other suspects with warrants out shortly, and have yet to publicize the names of those arrested lest it compromise the ongoing investigation.

According to the Brazilian newspaper O Globo, the group used the encrypted messaging application Telegram to meet and communicate, as well as organize plans to stage terrorist attacks at the Games in two weeks. The group, calling itself  “Supporters of Sharia,” included one underaged suspect. All those arrested were in Sao Paulo and Paraná states. They are being charged with “preparatory acts” for terrorism for planning to buy an AK-47 from a website in Panama.

In addition to planning a terrorist attack, officials say they group had celebrated multiple Islamic State attacks online and pledged allegiance to caliph Abu Bakr al-Baghdadi in their Telegram channel.

“There was an initial contact with the Islamic State. There was an oath,” Brazilian Minister of Justice Alexandre de Moraes told police. “There followed a series of preparatory acts, then this group came to understand that, with the Olympics, Brazil could become a target.”

CNN quotes de Moraes as describing the group as “absolutely amateur,” even discussing how they needed to find a way to learn how to shoot guns before they could properly execute an attack. The decision to seek the purchase of a firearm online, de Moraes noted, also belied their inexperience.

Brazil did not have a law to prosecute terrorist activities until March; these suspects will be the first to be tried under the new provisions, which prohibit the “promotion, creation, integration, or assistance in person or through an intermediary” of terrorist organizations, as well as “carrying out preparatory acts.” These suspects will be tried on the latter element of the crime. They face up to 30 years in prison for their association with ISIS.

The arrests follow the news of a declaration of allegiance to the Islamic State from Brazil by a group calling itself Ansar al-Khalifah Brasil, or Soldiers of the Caliphate in Brazil. The pledge is the first of its kind in Latin America, surfacing on the Telegram app and threatening terrorist attacks on events at the Summer Olympics. The pledge surfaced after authorities confirmed the existence of a Portuguese-language Islamic State channel on Telegram. Reuters identified the man behind the Portuguese ISIS propaganda as using the pseudonym “Ismail Abdul Jabbar al-Brazili.”

While authorities are focusing on domestic Islamist activity, a report in the Argentine outlet Infobae stated that at least four travelers planning to attend the Olympics have been barred from Brazil due to having ties to terrorist groups on their records.

In March, Navy Adm. Kurt Tidd, the top U.S. military commander in Latin America and the Caribbean, warned that American intelligence sources believed that the Islamic State was planning to increasingly target individuals in the region for radicalization. “We see that radicalization is occurring,” he said at a public event in July, reiterating concerns that nations like Brazil, which have such little history of terrorist activity that they only recently passed their first anti-terror law, would become vulnerable for ISIS recruiting.