European Commission President Jose Manuel Barroso vowed European officials will `` respond to the any deterioration on the ground '' with `` targeted measures against those responsible for violence and use of excessive force . '' NEW : ` > > Ukraine 's president declares a truce and the start of negotiations . Opposition leader says `` now we will see ' if president `` will stick to his word '' Western powers ramp up the political pressure , especially on Ukraine 's president .
NEW : ` > > Ukraine 's president declares a truce and the start of negotiations . Opposition leader says `` now we will see ' if president `` will stick to his word '' Western powers ramp up the political pressure , especially on Ukraine 's president .