There is no end in sight to the conflict in Syria, the Foreign Secretary has said, despite plans for fresh meetings with the Russian government this weekend.
William Hague said Britain stood ready to help the Syrian people when president Bashar Assad inevitably leaves office.
But he said there was no obvious route out of the current impasse.
He said: "It remains a deeply depressing and frustrating crisis. It is deteriorating and on current trends it will continue to deteriorate, leading to an even greater humanitarian crisis.
"We continue our efforts to make diplomatic progress, including with Russia - I will meet the Russian foreign minister again this weekend, but there is no sign of any breakthrough.
"In the absence of that we will be one of the leading countries delivering humanitarian aid, supporting the opposition in non-lethal ways and helping with other countries to prepare for the eventual day after Assad when the Syrians will need our help all the more."
Following reports that two people have been arrested at Heathrow suspected of being en-route to Syria to support alleged terrorist activity, Mr Hague said he could not comment on the specifics but added that Britons should not be in Syria or travelling to the country.
He said: "There is some evidence there are people (here who want to join the fighting). We could strongly advise them not to do so.
"On the general subject we are clearly very vigilant about this, about people either passing through the UK or British nationals who want to commit acts of violence anywhere, we are always vigilant about that.
"But we also advise all British nationals to leave Syria, not to go to Syria, we don't supply ourselves anything that could contribute to lethal action inside Syria and we don't want individuals to do that either."