Chile police use water cannons on fans
Thousands of fans waving Chilean flags, blowing horns and chanting "Viva Chile!" poured into downtown Santiago to watch their national side's second World Cup game on giant screens outside the presidential palace and on street corners.
"As of now, there are 70 detentions, the majority of which are for disorder," a police spokesman said.
Football is Chile's favourite sport, and brawls often follow major matches.
Police detained more than 80 people last week following Chile's victory over Honduras, which came 48 years to the day after they had last won a World Cup match - a 1-0 win in a third-place playoff against Yugoslavia on home soil in 1962.
Monday's win over Switzerland pushed Chile into the lead of its World Cup group, with six points.