OUAGADOUGOU, Burkina Faso (AP) — An unknown assailant threw a flammable bottle into a mosque in Burkina Faso's capital, wounding six people, the government spokesman said Sunday.

Investigations into the Friday evening attack are ongoing, Remis Fulgance Dandjinou told The Associated Press.

Security Minister Ousseni Compaore visited the site of the Friday evening attack and met with the victims on Saturday, according to a Facebook post from the ministry.

A 30-year-old woman who arrived at the mosque for evening prayers shortly after the attack told AP that people were crying and some were lying on the ground with burns. She spoke on condition of anonymity for fear of her safety.

A note left on the ground nearby said: “Close the mosque or we’ll launch grenades at you," she said.

Burkina Faso has been reeling from attacks linked to al-Qaeda and the Islamic State group for five years. More than 2,100 people have been killed this year due to violence, seven times larger than the number from two years ago, according to the Armed Conflict Location and Event Data Project.

Burkina Faso experts say that years of extremist violence could be fueling anti-Islamic sentiment.

“The attack represents emerging signs of divisions observed in areas of conflict now spreading to the capital and manifesting in violence with an Islamophobic dimension,” said Heni Nsaibia, a Sahel researcher.

Others worry the attack signifies the government’s inability to secure the country, two weeks before presidential and legislative elections.

“The attack signifies that security and intelligence services are not sufficient in Ouagadougou, said Siaka Coulibaly, with the Center for Public Policy Monitoring by Citizens. “This incident will increase fear and make people more afraid."