John Sullivan, in an interview with Reuters, spoke about the difficulties the American diplomatic mission had to face in Russia.

The Russian invasion of Ukraine has further complicated the difficult work of the U.S. Ambassador to Russia, John Sullivan, opposing the Kremlin’s threats of using nuclear weapons and severing diplomatic relations, despite the fact that the embassy staff has now decreased to one tenth of the usual level.

“Two and a half years ago it was very bad,” Sullivan recalls of his arrival in Moscow in January 2020. “It got even worse.”

However, so far, according to Sullivan, his meetings with representatives of the Russian Ministry of Foreign Affairs “have not been personally offensive or hostile.”

“The security situation here is not much different from what it was a month ago, six months ago,” Sullivan says. “But it can change at the discretion of the host government within a minute.”

Relations between the United States and Russia were already in the coldest state since the end of the Cold War, when former American President Donald Trump appointed Sullivan to the post of ambassador to Moscow.

Prior to that, Moscow in March 2018 ordered the closure of the U.S. consulate in St. Petersburg. Consulates in Vladivostok and Yekaterinburg were closed after Sullivan’s arrival. Now the embassy in Moscow remains as the only active U.S. diplomatic mission in Russia.

However, the embassy staff has been reduced from 1,200 people in 2017 to about 130 people, half of whom are marines and security personnel.

In April 2021, Washington recalled Sullivan for consultations. Joe Biden decided to keep him in this post.

Following the decree of Russian President Vladimir Putin, the Russian government in May 2021 ordered the embassy to dismiss dozens of Russian citizens who performed tasks critical for the diplomatic mission. This forced diplomats to stop processing all types of visas, except for vital ones.

Hopes of easing tensions increased when Sullivan and his Russian counterpart in Washington returned to their posts last June, and Biden and Putin met in Geneva the same month.

But relations deteriorated again after the Russian invasion of Ukraine.

“As far as diplomatic relations are concerned, we are at the level of the Mariana Trench,” says Sullivan, referring to the deepest ocean trench on the planet.

A few days after the invasion began, Putin put Russian nuclear forces on high alert, citing aggressive statements by NATO leaders and economic sanctions against Moscow.

American officials say they are concerned about the veiled threats of nuclear war that they continue to hear from the Russian authorities, including drawing comparisons with the 1962 Caribbean crisis.

Sullivan says he takes seriously the threats coming “from the very top of the Russian government” to sever diplomatic relations, arguing that “the Russians are not engaged in rhetorical outpourings.”

“The United States does not want to close its embassy. President Biden doesn’t want to recall me as an ambassador. But it’s not something that necessarily depends only on us,” Sullivan says.

In February, Moscow expelled Sullivan’s deputy from the country, and recently demanded the dismissal of 37 more embassy employees by July. This could lead to the fact that the diplomatic mission would turn into a virtual “caretaker,” guarded by a small contingent, a source in the Department of State says.

The embassy has already lost an elevator technician, and the possible dismissal of the two remaining electricians in the state may become a serious security problem.

An increase in the number of late-night conversations with Washington as tensions in Ukraine escalated prompted Sullivan in February to move out of Spaso House, an elegant embassy residence located 15 minutes from the embassy building.

According to Sullivan, he moved to a more modest townhouse where his deputy lived before he was kicked out of the country, located within walking distance to the embassy.

According to Sullivan, if diplomatic relations are severed, which will require the closure of the embassy, he will no longer be able to fulfill one of his most urgent tasks: to protect the interests of Americans detained in Russia. They include basketball player Brittney Griner, former Marine Trevor Reed, who went on a second hunger strike, and Paul Whelan.

“I told my colleagues [at the Department of State] that they would have to use a crowbar to get me out of here, because I won’t leave until either they kick me out or the president just tells me, ‘Look, you have to come home,'” the ambassador says.

Sullivan said he wants to “be here and at least protect those Americans who remain behind bars.”