Britain and Europe must tackle the "evil" Bashar al-Assad regime in Syria and Islamic State militants to stem the ongoing refugee crisis, George Osborne has said.
The Chancellor said the UK must offer asylum to those genuinely fleeing persecution but also boost aid, defeat smuggling gangs and deal with the conflict in Syria.
He said: "Countries like Britain always have, we are one of the founders of the asylum system. We will take, as the prime minister said, thousands more.
"But at the same time, you've got to make sure you've got aid going into the refugee camps on the borders ... We've got to defeat these criminal gangs who trade in human misery and risk people's lives and kill people.
"You've got to deal with the problem at source, which is this evil Assad regime and the ISIL (Islamic State) terrorists, and you need a comprehensive plan for a more stable, peaceful Syria. A huge challenge of course, but you can't just let that crisis fester."
Hundreds of refugees have started walking from Budapest to Vienna, a day after around 1,000 began a similar journey.
A Reuters witness said the group had set off from Budapest's Keleti railway station on foot to begin the 150-mile trip to the Austrian capital.
Hungary sent about 4,500 migrants to the Austrian border by bus overnight, including those who were walking on the motorway.
Hundreds of refugees have arrived in Germany after being transported on a special train.
Around 450 people arrived at Munich railway station after Austria and Germany agreed with Hungary to allow migrants to cross their borders.
Police said they would now be escorted onto a city train to take them to an emergency registration centre nearby.
Authorities expect between 5,000 and 10,000 refugees to come to Germany from Hungary via Austria on Saturday.
Austria's interior minister said 6,500 refugees have reached Austria, of which 2,200 were already on their way to Germany.
German police say they are expecting up to 10,000 refugees coming from Hungary via Austria today.