Kerry meanwhile said that Russia could be an "extremely constructive player" in finding an eventual peace settlement in Syria, which has been consumed by civil war for more than four years.
"I called on every NATO ally to step up support in the fight against Daesh (IS), striking at the organisation's core in Syria and Iraq," Kerry said after a meeting of foreign ministers from the 28 NATO states in Brussels.
Kerry praised British Prime Minister David Cameron as Britain's parliament looked set to vote in favour of joining the US-led bombing campaign against IS in Syria. Britain's attacks are currently limited to Iraq.
"We are very pleased with efforts by prime minister Cameron to go to parliament," Kerry said.
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"It is a very important step. We applaud his leadership."
Kerry said he hoped for constructive steps by Russia, which is also carrying out its own air campaign against jihadists in Syria but had one of its warplanes shot down by NATO member Turkey recently.
"We welcome Russia's engagement in the Syria process," Kerry said.
"As long as they're focused on Daesh and as long they are genuine in wanting to be part of implementing the Geneva (accords), they can be an extremely constructive and important player in reaching a solution," he added.
"I think the world would welcome that kind of cooperative effort."
Kerry also played down any threat to Russia from NATO, which announced today that it had invited Montenegro to be its 29th member despite warnings from Moscow which opposes NATO's expansion eastwards.
"NATO is a not a threat to anybody... Not an offensive organisation, not focused on Russia per se. I would say to Russia and any other country - this is not focused on them specifically.