it s one of the biggest bomb bombardance in a while. what have we heard, richard? reporter: the opposition in homs has managed to put out that live video feed. they ve done it in the past but not for sustained period of time like they ve been doing today, putting out direct pictures showing the shelling of homs. we ve seen plumes of smoke rising from the city. according to opposition sources, at least 50 people have been killed nationwide, many of them in homs. and the u.n. is concerned. it wants observers to go to homs. i spoke not long ago with a very senior western diplomatic source. and this is someone who s very close to the situation and developments going on in syria.