NEW : Shield-wielding riot police clash with protesters early Monday morning . The clashes began after a group of about 100 people marched through the streets chanting slogans against President Viktor Yanukovych. Protesters storm the country 's interior ministry and attack PM 's car .
NEW : Shield-wielding riot police clash with protesters early Monday morning . PM declares state of emergency in Bangkok and surrounding area . Protesters storm the country 's interior ministry and attack PM 's car .