Irish police evacuated about 100 homes today after they discovered a “suspicious object”, reported to be three mortars, in a van.According to the Police Service of Northern Ireland (PSNI), army experts were called to the Letterkenny Road area of Derry after they discovered the device late Monday, reported Sky News.Two men aged 35 and 37 were arrested and police are linking the incident with dissident republican activity.Detectives later arrested a third man today in connection with the security alert following a search of a property in the city, a PSNI spokesman said.“Police are currently dealing with a security alert in the Letterkenny Road area of Derry, following the discovery of a suspicious object in a vehicle,” a PSNI spokesman said