A £190m aid package has been announced by the International Monetary Fund to help Ebola-hit countries in Africa.
The announcement came at the G20 summit in Brisbane, Australia.
Member states welcomed the aid package and said they were "committed to do what is necessary to ensure the international effort can extinguish the outbreak and address its medium-term economic and humanitarian costs".
David Cameron and Vladimir Putin have met at the G20 summit in Australia, amid warnings that European leaders could impose further sanctions on Russia over the Ukraine crisis.
After being photographed shaking hands, the pair then held discussions in private.
Speaking earlier, the Prime Minister said the situation in Ukraine was "heading in the wrong direction" and warned Putin against trying to "bully" its neighbour.
He said: "What we need is for Russia to change track and to stop destabilising Ukraine [...] and to allow that country to make its own choices about its own future.
"That's not the direction we're heading in," he added.
Barack Obama has attacked Russia for its stance in the Ukraine crisis as European nations threatened further sanctions against the country.
Speaking on the sidelines of the G20 summit in Australia, the US President said his country was at the forefront of "opposing Russia's aggression against Ukraine, which is a threat to the world, as we saw in the appalling shoot-down of MH17".
European Council President Herman Van Rompuy said Moscow must stop supplying weapons and troops to Ukraine and would face additional sanctions if it did not push rebels in the east of the country to accept a ceasefire.
He said Europe's foreign ministers would meet on Monday to assess whether further steps - including more sanctions - should be placed on Vladimir Putin's nation.
David Cameron has accused Vladimir Putin of "machismo" after the Russian President had a fleet of warships sent to Australia in tandem with his appearance at the G20 summit of world leaders.
Australian PM Tony Abbott said the move was part of a "regrettable pattern" of Russian military assertiveness and claimed Putin seemed to be attempting to recreate the "lost glories" of the Soviet Union.
Cameron joked: "I didn't feel it necessary to bring a warship myself to keep myself safe at this G20, and I'm sure that Putin won't be in any danger."
The British Prime Minister is expected to meet Vladimir Putin today on the fringes of the G20 summit in Australia.
Officially, the meeting is focusing on economic growth and jobs but is rapidly developing into a showdown between the Russian president and other leading world powers.
Mr Abbott, who is hosting the gathering of the world's 20 leading economies, has also called for an apology from Russia for the downing of the Malaysia Airlines jet MH17 over Ukraine, which killed 38 Australians in July.
Six of the ceramic poppies from the Tower of London Remembrance display are to be given to Commonwealth leaders at the G20 summit.
David Cameron will present the flowers to the summit's host, Australian prime minister Tony Abbott, fellow PMs Narendra Modi of India, John Key of New Zealand, Stephen Harper of Canada, Lee Hsien Loong of Singapore and President Jacob Zuma of South Africa.
Each of the 888,246 poppies created by artist Paul Cummins represents a British or Commonwealth casualty of the First World War.
The artwork, marking the centenary of WWI, was viewed by an estimated five million visitors.
Mr Cameron said: "The extraordinary poppy display at the Tower of London caught the imagination of so many people across Britain and I wanted to share some of that with my fellow Commonwealth leaders, recognising the sacrifice their countries made to secure our freedom."
David Cameron will use the G20 summit in Brisbane to put pressure on fellow world leaders to provide more to tackle the Ebola crisis.
While the UK has pumped £230 million in official funds into the fight against the killer virus, some of the other 19 leading economies have provided little or nothing to help.
Mr Cameron has persuaded Australian prime minister Tony Abbott to put Ebola on to the G20 agenda.
He is expected to put particular pressure on countries like Brazil, who have only donated £2 million, and Mexico and Indonesia, who have given even less, for support.
Other G20 countries regarded as lagging behind in the international response include South Korea and Argentina.
Speaking ahead of the two-day summit, Mr Cameron said: "It's not just about money, it's also about getting the world together to try to produce and license these vaccines faster and we are making a particular push on that in the next 48 hours."
US President Barack Obama has arrived in Australia to join other world leaders at the G20 summit in Brisbane.
The G20 summit in St Petersburg exposed stark divisions between host Vladimir Putin and US President Obama over Syria.Read the full story ›
The emir of Kuwait, Sheikh Sabah al-Ahmad al-Jaber al-Sabah, is due to visit President Obama in Washington on September 13 to discuss Middle Eastern issues, the White House said.
A statement said: "The President looks forward to discussing with the emir a wide range of critical interests and important developments in the Gulf region and broader Middle East."
The visit comes as Mr Obama seeks to gain Congressional support for punitive strikes against Syria in the wake of a chemical attack.
President Obama will address the US nation on Syria on Tuesday.