Britain will do more to help victims of the Syrian civil war, William Hague pledged as the United Nations revealed the number of refugees had passed two million.
The Foreign Secretary said the Government remained "highly active" in seeking an end to the violence but insisted there were no plans to seek a fresh vote on UK involvement in military strikes.
Efforts would instead be concentrated on a diplomatic push to secure a stalled peace conference, with Prime Minister David Cameron to press regime ally Russia on the issue at the G20 summit later this week.
The scale of the human toll of the conflict - which has claimed more than 100,000 lives, came in the latest UN figures which showed 1.8 million have fled to neighbouring countries in the last year.
With another 4.25 million displaced within the country, a third of the population have now been forced from their homes in what UN High Commissioner for Refugees Antonio Guterres called the "great tragedy of this century".
"The UK is the already the second largest donor, supporting over 900,000 citizens and we will do more," Mr Hague told MPs as aid agencies warned overstretched refugee camps needed a massive funding boost.
"The president of the Syrian National Coalition will visit London on Thursday when we will discuss further support to save lives, promote political dialogue in Syria and advance the holding of a second Geneva conference.
"It is another testimony to the callousness of this regime towards its own people that not only have they killed so many tens of thousands but also that they obstruct the delivery of aid, including medical supplies, to people in their own country who desperately need it."
Downing Street denied any split with the Cabinet - which discussed the crisis this morning - over the prospect of Britain still joining military strikes against the Syrian regime in response the use of chemical weapons.
Mr Cameron ruled out the UK joining action planned by the US and after being defeated on the issue in the Commons. US president Barack Obama's decision to delay action while he too seeks Congressional support has prompted calls for a rethink however, with London Mayor Boris Johnson earlier renewing calls for the option to be kept open.