Ukraine appeared to threaten to target a key Russian bridge across the Kerch Strait to Crimea by publishing details of its construction on Thursday.
Ukrainian military intelligence published what it said were official Russian construction details about the bridge, although it was not immediately possible to establish the authenticity of the nearly 300-page document.
It was published a day after Ukrainian General Dmytro Marchenko said the bridge would be "target number one" if Kiev obtained the necessary weapons. He said Moscow used the bridge to transport supplies to Crimea and southern Ukraine.
The 18-kilometre bridge cost billions to build and has linked Crimea to the Russian mainland since 2018.
Russian government spokesperson Dmitry Peskov said all precautions were in place to ensure the security of Crimea. He said the Kremlin was aware of Kiev's latest threats to target the bridge.
Moscow has threatened to bomb Kiev if the structure is attacked.
Foreign Minister Sergei Lavrov said that Marchenko's threat ran counter to promises Ukrainian President Volodymyr Zelensky has made to Western partners to not use long-range weapons to attack Russian territory.
However, Kiev still sees occupied Crimea as part of Ukraine.