Russian President Vladimir Putin said Tuesday he is considering expelling another 155 State Department personnel from Russia, which would further escalate the diplomatic tit-for-tat with the U.S.

"So strictly speaking, the number of American diplomats in Moscow should be not 455 but 155 fewer, if we are talking about parity," Putin told reporters at a press conference in China. "So, we reserve the right to take a new decision on the number of American diplomats in Moscow. We will not do this immediately but will see how things develop."

Putin's comment was a reference to the U.S. claim that the two countries are now at "parity" after the U.S. closed three Russian facilities last week. That action was a response to Russia's cut in U.S. staff, which was a response to new U.S. sanctions imposed against Russia. Putin had capped the number of State Department personnel in Russia at 455, the same number of Russians operating in the United States. But Putin argued Tuesday that even the 455 figure represents an imbalance, because some of the Russians in the U.S. work at the United Nations.

"Strictly speaking, they are not diplomats accredited at the US Department of State but diplomats working at an international organisation," he said. "When the United States wanted the UN to be headquartered in New York, it pledged to properly ensure its operation."

Both Russia and the United States are trying to win the diplomatic spat without deepening the feud too egregiously. Tillerson's team closed three facilities, but simultaneously argued for an end to the flap.

"While there will continue to be a disparity in the number of diplomatic and consular annexes, we have chosen to allow the Russian government to maintain some of its annexes in an effort to arrest the downward spiral in our relationship," State Department spokeswoman Heather Nauert said last week. "The United States hopes that, having moved toward the Russian Federation's desire for parity, we can avoid further retaliatory actions by both sides and move forward to achieve the stated goal of both of our presidents: improved relations between our two countries and increased cooperation on areas of mutual concern."

The consternation has built for years, but the most immediate cause is Russian interference in the 2016 elections. Then-President Barack Obama expelled 35 Russian officials and seized two facilities in December, to punish that interference and the harassment of the U.S. personnel operating in Russia. Putin delayed retaliating, but then Congress tied his hands by passing sanctions legislation, supported by an overwhelming majority of lawmakers, that codified Obama's sanctions and added additional measures punishing Russia's invasion of Ukraine and partnership with Iran in support of Syrian President Bashar Assad.

Russian officials sent mixed signals in response to the latest decision. Putin's spokesman countered with a promise of additional retaliation, but other members of the administration softened the threat. Russian Foreign Minister Sergey Lavrov, in particular, absolved President Trump of responsibility for the tension and blamed Congress instead.

"We understand that efforts are being made to corner them [the Trump administration] at every opportunity, so we don't believe it is necessary to take any active steps concerning relations with the U.S.," Lavrov said Friday.