Kerry was speaking in Kyiv as the German and French leaders, Angela Merkel and Francois Hollande, arrived in the Ukrainian capital with a new proposal to end the conflict, which they planned to discuss in Moscow on Friday, Censor.NET reports citing Reuters.
"The president is reviewing all of his options, among those options is the possibility of providing defensive systems to Ukraine," Kerry told a joint news conference with Ukrainian Prime Minister Arseny Yatseniuk.
"The president will make his decision soon but not before he has had a chance to hear back from myself and others."
Kerry said Hollande and Merkel would make a "counter-proposal" to a peace plan laid out by Russian President Vladimir Putin in mid-January, which was not approved by Kyiv.
Washington backed the initiative and any solution to the crisis in east Ukraine could not be a "one-sided peace", he said.
"That is very much the diplomacy that is needed right now and it is particularly helpful because we do have key decisions on the choices we need to make on the road ahead," Kerry said, adding he would meet Merkel in Munich on Saturday.