The U.S. intelligence community assesses Russia is preparing for a "prolonged conflict" in Ukraine that is likely to become "more unpredictable and escalatory" due to a "mismatch" between Vladimir Putin's ambitions and military capabilities, Director of National Intelligence Avril Haines testified Tuesday.

Why it matters: Both Russia and Ukraine believe they can continue to make progress militarily, turning the conflict into a "war of attrition" with no "viable" prospects for peace negotiations in the near term, Haines told the Senate Armed Services Committee.

The big picture: While Russian forces have refocused on the eastern Donbas region after failing to capture Kyiv in the first few weeks of the war, the U.S. views this as "only a temporary shift."

• "We assess President Putin is preparing for a prolonged conflict in Ukraine, during which he still intends to achieve goals beyond the Donbas," Haines said.

Zoom in ... Putin has at least four "near-term military objectives," according to the U.S. intelligence community:

• Fully capture and establish a "buffer zone" in the Donbas, where Russian-backed separatists have declared "people's republics."
• Encircle Ukraine's military west of the Donbas "in order to crush the most capable and well-equipped Ukrainian forces fighting to hold the line in the east."
• Consolidate control of the land bridge that Russia has established from the Donbas along the southern coast of Ukraine to Crimea, allowing Russian forces to occupy the Kherson region and control Crimea's water supplies.
• The U.S. also sees "indications" that Russia wants to extend the land bridge further west to capture the historic port city of Odessa and connect with the pro-Russian breakaway region of Transnistria in Moldova, fully cutting Ukraine off from the sea.

Between the lines: The U.S. views it as "increasingly unlikely" that Russia will be able to establish full control over the Donbas or extend the land bridge to Transnistria, especially without a broader mobilization of Russia's reservists.

• "But Putin most likely also judges that Russia has a greater ability and willingness to endure challenges than his adversaries and he is probably counting on U.S. and EU resolve to weaken as food shortages, inflation and energy prices get worse," Haines warned.
• The U.S. believes Russia will continue to use "nuclear rhetoric" to deter the West from providing further military assistance to Ukraine, but that Putin "would probably only authorize the use of nuclear weapons if he perceived an existential threat to the Russian state or regime."
• "We're supporting Ukraine, but we also don't want to ultimately end up in World War III and we don't want to have a situation in which actors are using nuclear weapons," Haines said.