NEW : Prime Minister Boyko Borisov 's government has resigned from office . NEW : Parliament is expected to vote on whether to accept the resignation Thursday . Comment: The president of Bulgaria, Rosen Plevneliev ( a former communist ) was elected in 2010 and had promised that he would not run for reelection this year because it would be too difficult
NEW : Prime Minister Boyko Borisov 's government has resigned from office . NEW : Parliament is expected to vote on whether to accept the resignation Thursday . Bulgaria has been roiled by public protests for more than a week .