Authorities were tracking extremist activity on social networks and identified two young men preparing to commit an attack with explosives The announcement came days after an Islamic extremist stabbed five people in the heart of Paris PARIS: France"s interior minister says authorities have thwarted a possible attack using ricin or explosives and arrested two brothers. Interior Minister Gerard Collomb told BFM television Friday that authorities were tracking extremist activity on social networks and identified two young men "preparing to commit an attack with explosives or ricin." He said the young men were of Egyptian origin but didn"t indicate their nationality or provide other details about where or when they were arrested. He said the men notably had tutorials on how to make poison using ricin. No other information was immediately released. The announcement came days after an Islamic extremist stabbed five people in the heart of Paris, and as the country is still on edge after a string of deadly attacks in recent years.