In just 140 characters, Donald Trump could have reignited an international nuclear arms race on Twitter Tuesday afternoon. The move could cost the U.S. billions and have implications for decades to come.

On Friday, the president-elect’s call for the United States to "greatly strengthen and expand its nuclear capability" was met with an apathetic response from Russian President Vladimir Putin, who noted Trump had already previously stated his desire to bolster America’s nuclear defense system along the presidential campaign trail. Putin acknowledged the U.S. has more nuclear missiles than his nation, "but what we say is that we are stronger than any aggressor, and this is the case," he said while speaking at his annual press conference in Moscow.

"As for Donald Trump, there is nothing new about it, during his election campaign he said the U.S. needs to bolster its nuclear capabilities and its armed forces in general," Putin said Friday. The president noted his nation would reduce its defense spending to 2.8 percent of its gross domestic product by 2019, down from 4.7 percent in 2016, though he added, "this will not have an impact on our plan to increase our defense capabilities."

Putin detailed the Russian’s defense program’s current mission to modernize its existing nuclear warheads and missiles in order to pierce missile defense systems the United Nations has established in neighboring regions.

Meanwhile, Trump’s tweet leaves a bevy of questions about the next White House administration's intentions on nuclear defense expansion unanswered. The New York Times detailed a number of theoretical explanations for Trump’s tweet in a dissection published Thursday afternoon. The publication suggested Trump could be planning to modernize the U.S.’ existing nuclear forces, as President Barack Obama announced in a 64-page report on his nuclear policy proposals in 2010. In this case, Trump would only slightly upgrade Obama’s existing plans. Obama’s plans were expected to cost nearly $1 trillion.

Trump shrugged off suggestions of a reignited arms race on Friday, telling MSNC’s Mika Brzenzinski: "Let it be an arms race. We will outmatch them at every pass and outlast them all."

However, Trump could also wish to invest billions of more dollars into the nuclear defense system in an effort to make nuclear capabilities faster and more powerful. The move would further strengthen ties with nuclear-protected nations like South Korea but potentially cause riffs between nuclear-strongholds China and Russia.

Trump’s tweet could also signal the next administration intends on expanding its total sum of nuclear warheads around the world. However, it was unclear whether the White House would immediately stockpile those new missiles or move them into active deployment.

Until the president-elect holds a press conference – it’s been 148 days since his last — or releases a detailed report of his goals in regards to the nation's nuclear defense system, Trump’s tweets about nuclear warheads will likely continue to make waves online, with many users immediately fearing a potential new nuclear arms race.