MOSCOW (AP) — With a sweeping cut in the number of U.S. diplomatic personnel in Russia, President Vladimir Putin has raised the stakes further in an escalating rift with the United States.

The reductions, reminiscent of massive Cold War-era expulsions of diplomats, follow stiff, new sanctions against Russia approved by the U.S. Congress.

A look at the Russian-U.S. spat and its potential repercussions.

DIPLOMATIC TIT-FOR-TAT

In December 2016, following allegations of Russian meddling in the U.S. presidential election, President Barack Obama ordered the expulsion of 35 Russian diplomats and the closure of two Russian diplomatic recreational retreats.

Putin denied interfering in the U.S. vote and strongly protested Obama's move, but he refrained from immediate retaliation, hoping that President Donald Trump would reverse the action.

Russian and U.S. diplomats have discussed the issue for months but failed to reach an agreement.

Putin finally decided to respond following an overwhelming approval of a new package of anti-Russian sanctions by the U.S. Congress.

The Russian Foreign Ministry declared that, as of Sept. 1, the U.S. Embassy and consular personnel will be capped at 455, the number that Russia has in the United States. Putin said it means that the U.S. will have to cut 755 of its staff, calling the blow "painful." Russia also announced the closure of a U.S. recreational compound and warehouse facilities.

It's the harshest retaliatory exchange since 1986, when the United States and the Soviet Union expelled dozens of diplomats.

COOPERATION IN SYRIA

During the first Trump-Putin meeting on the sidelines of the Group of G-20 summit in Germany earlier in July, Russia and the U.S. sealed a deal on a safety zone in southwestern Syria. Moscow called the agreement a major breakthrough that could help end Syria's devastating civil war.

Even as he laid out drastic cuts on the U.S. Embassy staff in televised comments Sunday, Putin emphasized the importance of the Syria deal, saying it signaled that Moscow and Washington could cooperate on global issues despite their differences. He noted the accord addresses the interests of Russia, the U.S. and regional players, including Jordan and Israel.

Despite the tensions with the U.S., Moscow probably will try to stick to the safe zone agreement, which helps secure its role as a key player in the Syrian crisis on equal par with the U.S.

UKRAINIAN CRISIS

A surge in U.S.-Russia tensions augurs increased instability in eastern Ukraine, where Moscow-backed rebels are waging a separatist campaign.

While Putin has praised the appointment of a U.S. envoy to help secure a fragile 2015 peace deal, skirmishes between the separatists and Ukrainian troops have continued in the east. The U.S. and other Western countries imposed crippling sanctions on Russia over the annexation of Crimea from Ukraine and Moscow's support for the insurgency.

With many in Congress pushing for sending U.S. weapons to Ukraine — a move Russia considers a red line — the conflict could grow even more violent.

NORTH KOREAN MISSILE TESTS

As the Russia-U.S. ties grow increasingly strained, Russia may become more reluctant to support U.S. efforts to raise pressure on North Korea to force it to curtail its missile and nuclear programs.

While Russia has criticized North Korea over its latest missile tests, it also has strongly warned the U.S. against scaling up economic sanctions against the country.

Earlier this month, Russia teamed up with China to urge the U.S. and South Korea to refrain from large-scale military exercises to encourage the North to show restraint.

ENERGY AND SPACE

Putin said U.S.-Russian cooperation also has continued in several key areas, pointing to U.S. companies' involvement in energy projects in Russia.

The two countries also have maintained close cooperation on space exploration, with U.S. astronauts continuing to ride Russian spacecraft to the International Space Station, pending the development of new U.S. spacecraft.

Putin noted that Russia has levers to hurt the U.S. in a few areas where they cooperate, but he voiced hope he won't have to do that because such moves would hurt Moscow's own interests.