The Biden administration temporarily has stopped a military aid package to Ukraine that would include lethal weapons after Russia announced it would reduce troops stationed near its neighbor and in the lead-up to President Joe Biden’s summit with Russian President Vladimir Putin, Politico reported Friday.

The Washington Post first reported Tuesday that the administration had tabled the aid.

Politico, which cited a source saying the arms package remained intact and could be sent to Ukraine quickly, reported that National Security Council officials stopped the aid package, which included lethal weapons and is worth up to $100 million, according to four people familiar with internal deliberations.

The NSC had directed officials to form the package after the administration became concerned over a massive Russian military buildup near the border with Ukraine and in the Crimean Peninsula, according to three Politico sources.

Politico reported State Department and Pentagon officials assembled the proposal.

Short-range air defense systems, small arms and more anti-tank weapons were included in the package, two people with knowledge of the discussions told Politico.

The U.S. has provided Ukraine with about $2.5 billion in military aid — including unarmed drones, radios, and Javelin anti-tank missiles — since Russia’s 2014 invasion of the country and annexation of Crimea, Politico said.

The Post reported the administration considered the package in the spring as Russia sent more than 100,000 troops to near the Ukraine border.

Russia said it would begin reducing the number of troops at the border in late April, when the NSC then decided to table the aid package.

However, Politico said that despite Russia’s announcement, a top Ukrainian official said in May that about 100,000 Russian troops remained near its border and in Crimea, Al Jazeera reported. Biden officials that month told The New York Times that the number was closer to 80,000.

May was also when Russian Defense Minister Sergei Shoigu said his country was building 20 new military units to base in Western Russia, close to the Ukraine border.

Politico reported satellite images captured in May and June showed hundreds of trucks and other heavy equipment in newly constructed makeshift bases in Western Russia and at a major training range in Crimea.

“The reason they left those units is because they said that they intend to use them in Zapad 2021,” a large military exercise Russia holds every several years with Belarus, Michael Kofman, a senior research scientist in the Russia Studies at the Center for Naval Analyses, told Politico.

The Biden administration was concerned about the Russian buildup, which was larger than what was seen during the 2014 invasion of Ukraine.

Lethal military aid to Ukraine has concerned U.S. officials over the years because they worried about provoking Russia.

The Pentagon has approved two aid packages to Ukraine this year alone, totaling $275 million, Politico reported.

The Politico report came two days after Biden and Putin held a summit in Geneva. They agreed to hold arms control and cyber-security talks, and described meeting as pragmatic rather than friendly.