(CNN) — The United States upped pressure on Moscow over the Malaysia Airlines disaster as Secretary of State John Kerry drew a clearer line to Russia over its ties to rebels in Ukraine and the rocket system used to down the jet. He also noted on CNN that it was a “moment of truth” for Vladimir Putin.

Kerry and key congressional lawmakers from both parties especially sharpened the focus on Putin to, as Senate Intelligence Committee Chairman Dianne Feinstein said, “man up” and lead.

There was concern, however, that Russia’s behavior since Thursday’s destruction of Flight 17 by a missile the United States believes was fired by the Russian-backed rebels further underscores Putin’s hardening preference for Cold War-era politics.

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