NEW : At least 35 people have died in violence Thursday , an activist group says . Syria 's government has said it is fighting armed terrorists , and it maintains that the death toll is much lower than international observers and opposition groups say . The Arab League could impose economic sanctions Sunday if Syria ignores deadline . Comment: The United Nations says more than 3,500 have died since the protests began in March .
NEW : At least 35 people have died in violence Thursday , an activist group says . The Arab League could impose economic sanctions Sunday if Syria ignores deadline . Comment: The United Nations says more than 3,500 have died since the protests began in March .