600,000 people are due to attend this year's "Rock in Rio" music festival being held in Lisbon May 28 to 30 and again during the first weekend in June. More than 70 performers are scheduled to perform in the event, which is being held this year for the first time outside of Brazil. Earlier Defence Minister Paulo Portas told reporters Portuguese soldiers could be recruited to help police boost security during the Euro 2004 finals. "The law allows, under certain circumstances, that the armed forces play a role in the provision of internal security," he said. The Euro 2004 security measures were announced on the same day that private television station TVI reported Portuguese police were investigating clues which suggest that three Moroccans arrested over the weekend in Spain in connection with the bombings there had been in Lisbon just beforehand. The station, which cited unnamed police sources, did not say what evidence the authorities had to suggest that the suspects had been in Portugal recently. During his address to parliament, Figueiredo Lopes said that more than 20,000 security officials were providing extra patrols of airports, train stations, embassies, border crossing and other sensitive areas across the country since the Madrid bombings. "Although there has been no credible threat against Portugal, we have adopted a series of measures without giving in to a security paranoia," he said.