A Belgian prosecutor said Friday that police have arrested six people in connection with the Brussels bombings during a large police operation in the city. The prosecutor said that several houses were searched in Brussels, Jette and Schaerbeek and residents had reported [BBC report] explosions during the house-to-house raids. Those arrested have been detained for questioning and have not been charged with a crime.

The Islamic State (IS) [JURIST backgrounder], which has claimed responsibility for the attacks that left 31 people dead [CNN report], has been accused of war crimes on a massive scale in Iraq and Syria. IS also claimed responsibility for the November attacks in Paris [JURIST report]. Authorities have reported [USA Today report] that that evidence gathered in three countries shows a “close working relationship” between terrorists who struck in Brussels on Tuesday and in Paris in November. Authorities have detained at least 11 people in operations in Belgium, France and Germany and have confirmed that one of the suicide bombers at Brussels Airport was the bomb maker related to the two suicide vests used in the Paris attacks. According to US counterterrorism officials, the ongoing police operations suggest [CNN report] that authorities are working towards preventing the next attack; investigators know of additional plots [CNN report] in Europe in various stages of planning.