Secretary of State Rex Tillerson flew into Moscow Tuesday to confront the Kremlin over its support for Bashar al-Assad as the U.S. questioned if Russia was complicit in an alleged chemical weapons attack.
Tillerson is the first senior U.S. official to visit Moscow since President Donald Trump took office promising to seek closer anti-terrorist cooperation with Russia, but as he arrived relations were already tense.
Last week, the U.S. fired a volley of cruise missiles at a Syrian airbase in response to an alleged regime attack using a suspected nerve agent that killed at least 87 civilians in a rebel-held town, many of them children.
Russia, which along with Iran has deployed forces to help Assad in the six-year-old civil war, reacted with fury to the U.S. strike and continues to cast doubt on the regime's involvement in the chemical attack, to Washington's disgust.
Tillerson did not cancel his visit, however, and he will hold talks with his counterpart Foreign Minister Sergei Lavrov on Wednesday. It is not yet clear whether an expected meeting with President Vladimir Putin will go ahead.