The United Nations Joint Office for Human Rights says four people have been killed and 15 others injured amid clashes between security forces and protesters in eastern Congo.

The office said Tuesday that the U.N. mission in Congo has deployed a team to Goma, the capital of North Kivu province, to monitor the situation and investigate. It also said security forces arrested at least 37 people.

Protesters in Goma on Monday demanded that President Joseph Kabila step down at the end of the year if new elections are not held.

The U.N. mission says it condemns "all forms of violence and calls for the respect of fundamental rights and freedoms, including the rights to freedom of peaceful assembly and demonstration."