LONDON—Oil slipped towards $125 a barrel in volatile trading on Wednesday as investors assessed the U.S. ban of Russian oil imports and Russia announced a new ceasefire in Ukraine on Wednesday to let civilians flee. A view that the U.S. ban of Russian oil imports may not worsen shortages kept a lid on prices, traders said, as did talk that Ukraine was no longer seeking NATO membership after some news reports this week on the issue. “Maybe this is playing its part,” said Tamas Varga of oil broker PVM said of the Ukraine NATO membership issue. “The realization that the U.S. import ban might not materially make the current supply shock worse than it has been might have also triggered this bout of profit-taking,” he added. Brent crude fell $2.27, or 1.8 percent, to $125.71 a barrel at 1105 GMT, after earlier rising above $131. U.S. West Texas Intermediate (WTI) …