The nuclear agreement between Western powers and Iran was broadly welcomed by politicians, former world leaders and Middle East experts.
Sri Lanka is putting on a show ahead of Friday's Commonwealth summit - but it is being overshadowed by accusations of human rights abuses.
William Hague and his Friends of Syria counterparts have agreed to "provide urgently all the necessary material and equipment" to rebels.
William Hague is speaking in the House of Commons on the deal reached by the international community with Iran over its nuclear ambitions.
The Foreign Secretary has listed commitments made by Iran, saying these will prevent Iran from using its program to build nuclear weapons. In return some of the international sanctions will be suspended.
A deal struck after lengthy negotiations in Geneva, Switzerland, commits Iran to curb its nuclear activities for six months in exchange for limited and gradual relief from some sanctions, including access to £2.5 billion ($4.2 billion) from oil sales.
There are "legitimate concerns" about Iran's nuclear programme despite a deal reached with world powers, William Hague has acknowledged.
The Foreign Secretary insisted that the "first step deal" should "give us faith in the power of diplomacy" following a fundamental change in Iran's attitude.
Mr Hague told BBC Radio 4's World This Weekend he understood the scepticism of Israel and Saudi Arabia about Iran's commitment to the process.
"But this is the first time that Iran has entered into an agreement with other nations, with the international community, about what to do about its nuclear programme", he added.
Foreign Secretary William Hague has returned to London for a meeting with US Secretary of State John Kerry on the Middle East.
Mr Hague wrote on Twitter:
US Secretary of State John Kerry has arrived in the UK ahead of his meeting with Foreign Secretary William Hague on the Middle East peace process.
Mr Hague and Mr Kerry are also expected to discuss the latest developments in Syria and Libya.
Foreign Secretary William Hague and US Secretary of State John Kerry will have talks in London tomorrow on the Middle East, the State Department has said.
As well as further discussions on Iran, they are expected to consider the latest developments in Syria and the Middle East peace process.
Libyan officials will also be present at the meeting, the State Department added.
A number of British nationals remain unaccounted for following the typhoon in the Philippines, Foreign Secretary William Hague said.
Labour's call for Sri Lanka's President Rajapaksa to be blocked from taking up the role of Commonwealth chairman-in-office over the next two years has been dismissed by Foreign Secretary William Hague.
The role would see President Rajapaksa visit the UK next year for the Glasgow Commonwealth Games, and also take part in ceremonies to commemorate the 100th anniversary of the outbreak of the First World War.
The Foreign Secretary told the Today show: "[Sri Lanka] are chairing it now, from this meeting they are chairing it. This was decided when the Labour government was in power in 2009, so criticism of that from the Labour Party is from the less convincing end of opportunism and hypocrisy."
He added: "The Commonwealth operates by consensus, so when that's been agreed four years ago you can only change it again by consensus...It's not really a very practical thing for the opposition to say, nor does it fit with the decisions they made in the past."
The Foreign Secretary William Hague said he was calling on the Sri Lankan government to investigate allegations of war crimes in the country:
An important part of my purpose of coming to Sri Lanka was to meet members of the Tamil community as well as those working across Sri Lanka to promote human rights, reconciliation and accountability for past crimes.
I am pleased that the Prime Minister is visiting the north of Sri Lanka to see for himself the work that needs to be done to address the legacy of the conflict.
– William Hague
I am calling on the Sri Lankan government to conduct a transparent and independent investigation into alleged war crimes, improve Sri Lanka’s human rights record and for both the government and the TNA to work constructively together towards a political settlement that delivers meaningful devolution for the North of the country.