Assad should 'grant UN access' if he has 'nothing to hide'

Russia has added its voice to the mounting pressure on Syria over an alleged chemical attack.

A senior UN official is heading for Damascus to press for inspectors to be allowed to visit the site - and Moscow is now urging the Assad regime to co-operate.

The BBC spoke to Professor Fawaz Gerges from the London School of Economics who said "it defies logic that Assad would use such a large-scale chemical attack while UN inspectors are in Damascus".