KYIV, Ukraine — With critical talks approaching, the United States and Russia on Wednesday showed no sign either will relent from entrenched positions on Ukraine that have raised fears of a Russian invasion and a new war in Europe.

Speaking in Kyiv, U.S. Secretary of State Antony Blinken accused Russia of planning to reinforce the more than 100,000 troops it has deployed along the Ukrainian border and suggested that number could double “on relatively short order.” Blinken did not elaborate, but Russia has sent an unspecified number of troops from the country’s far east to its ally Belarus, which also shares a border with Ukraine, for major war games next month.

Ukraine, meanwhile, said it was prepared for the worst and would survive whatever difficulties come its way. The president urged the country not to panic.

Blinken’s visit to the Ukrainian capital came two days before he is to meet in Geneva with Russian Foreign Minister Sergey Lavrov. That follows a series of inconclusive talks last week that failed to ease rising tensions.

Russian military activity has been increasing in recent weeks, but the U.S. has not concluded whether President Vladimir Putin plans to invade or whether the show of force is intended to squeeze the security concessions without an actual conflict.

In Kyiv, Blinken reiterated Washington’s demands for Russia to de-escalate the situation by removing its forces from the border area, something that Moscow has flatly refused to do. And, Blinken said he wouldn’t give Russia the written response it expects to its demands when he and Lavrov meet in Geneva.

Meanwhile, a top Russian diplomat said Moscow would not back down from its insistence that the U.S. formally ban Ukraine from ever joining NATO and reduce its and the alliance’s military presence in Eastern Europe. Deputy Foreign Minister Sergei Ryabkov said Moscow had no intention of invading Ukraine but that its demands for security guarantees were non-negotiable.

The U.S. and its allies have said the Russian demands are non-starters, that Russia knows they are and that Putin is using them in part to create a pretext for invading Ukraine, which has strong ethnic and historical ties to Russia.

The former Soviet republic aspires to join the alliance.

Blinken urged Western nations to remain united in the face of Russian aggression. He also reassured Ukraine’s leader of NATO support while calling for Ukrainians to stand strong.

Blinken told Ukrainian President Volodymyr Zelenskyy that the U.S. and its allies were steadfast in backing his country and its democratic aspirations against Russian attempts to incite division and discord through “relentless aggression.”