KYIV — National security advisers from Europe and other allies visited Kyiv on Saturday to discuss security guarantees and economic support as a U.S.-led diplomatic push to end the nearly 4-year-old war in Ukraine intensifies. Ukranian President Volodymyr Zelenskyy, preparing to travel to Paris for a meeting with partners, said work on the peace proposals could now accelerate as Ukraine has shared all documents under discussion with the 18 national security advisers, including those on security guarantees.