The US will accept an extra 30,000 refugees from around the world over the next two years, Secretary of State John Kerry said on Sunday, as the Obama administration came under further pressure to take in more victims of the Syrian civil war.

Speaking as his predecessor Hillary Clinton urged America to “lead the world” in responding to the Syrian emergency, Kerry said the total number of refugees taken by the US yearly would rise from 70,000 to 85,000 next year and to 100,000 in 2017, Reuters reported.

“The need is enormous, but we are determined to answer the call,” Kerry said, during remarks in Berlin. Kerry reportedly did not say whether any of the additional refugees would be from Syria.

Earlier on Sunday, Clinton said the US should take in more than six times the 10,000 Syrian refugees that has been proposed by President Barack Obama.

“We’re facing the worst refugee crisis since the end of world war two, and I think the United States has to do more,” Clinton said on CBS. “And I would like to see us move from what is a good start with 10,000 to 65,000.”

Kerry’s predecessor as secretary of state said the US should vet applicants to prioritise welcoming the “most vulnerable” people who have fled the Syrian civil war, such as Christians and Yazidis who have faced religious persecution from Islamist militants.

Clinton’s remarks brought her into agreement with Martin O’Malley, the former governor of Maryland who is a rival for the 2016 Democratic presidential nomination. He urged Obama to accept 65,000 displaced Syrians during a flashpoint in the crisis earlier this month. A group of 14 Senate Democrats cited the same figure in a letter to Obama four months ago.

Clinton also urged United Nations secretary general Ban Ki-moon to convene an international meeting at this month’s annual general assembly in New York, in order to push states to commit more funding and support for the Syrian relief effort.

Speaking days after a senior US general disclosed that a $500m “train and equip” programme had resulted in only four or five American-backed Syrians actually fighting the Islamic State, Clinton conceded: “We have a failed programme.”

She stressed that she had urged Obama to begin such operations several years ago while serving as the most senior US diplomat.

“A lot of what I worried about has happened,” she said. “Where we are today is not where we were.”

Clinton said the US should persevere with arming moderate elements and provide more support to regional allies.

“I wouldn’t give up on ‘train and equip’, but I sure would push the Pentagon to take a hard look at why what has been done has been such a failure,” she said.

Hillary Clinton discusses the Syrian refugee crisis on CBS. Guardian

Turning to domestic politics, Clinton reiterated her apology for using only a personal email server during her tenure at the State Department, the disclosure of which has now dogged her campaign for several months.

“I’m sorry I made a choice that has raised all these questions,” she said, dismissing suggestions that her aides had felt unable to challenge her.

She also said her campaign was doing nothing to prepare for the possibility that Vice-President Joe Biden would join the Democratic presidential primary contest.

And in a rare comment directly naming Senator Bernie Sanders of Vermont, the leftwing firebrand who has overtaken Clinton in some opinion polls of Iowa and New Hampshire, the first two states to vote in the primary, Clinton said: “I know Bernie. I respect his enthusiastic advocacy.”