Trump Imposes New Authority on Russia Over Ukraine Incursion.

Trump administration ratcheted up pressure on Russia on Tuesday, unveiling sanctions on more than three dozen additional individuals and organizations that have participated in the country’s incursion in Ukraine.

The Treasury Department made the announcement on the same day that President Trump hosted his Ukrainian counterpart, Petro O. Poroshenko, at the White House to discuss a peaceful resolution to the conflict with Russia. The sanctions also came as Mr. Trump continues to face questions about whether his campaign colluded with Russia to help him defeat Hillary Clinton.

The new sanctions underscored the renewed tension in already abysmal relations between Washington and Moscow. On Monday, Russia threatened to target American and other coalition aircraft over Syria a day after an American fighter jet shot down a Syrian warplane.

Treasury Secretary Steven Mnuchin said there should be no sanctions relief for Russia until it meets its obligations under the Minsk agreements — the 2015 cease-fire deal between Russia and Ukraine.

“These designations will maintain pressure on Russia to work toward a diplomatic solution,” he said. “This administration is committed to a diplomatic process that guarantees Ukrainian sovereignty.”

Mr. Trump and President Vladimir V. Putin of Russia are expected to meet for the first time on the sidelines of the G-20 summit meeting in Hamburg, Germany, early next month. Sanctions are one of many potentially thorny issues on the table.

Mr. Putin was asked last week on his nationwide live call-in show whether Russia could weather sanctions indefinitely. He said the West had been trying to contain Russia for hundreds of years with such measures, with Russia’s 2014 annexation of Crimea the latest excuse.

In some ways, he said, sanctions have made the country stronger as it has grown more self-reliant, but they have also harmed the Russian economy and Western countries that interact with it. “All of these restrictions do not produce anything good, and we should work toward a global economy that functions without these restrictions,” Mr. Putin said.

Asked about the latest sanctions at a news conference on Tuesday, Sergey V. Lavrov, the Russian foreign minister, said that they were once again adopted “out of the clear blue sky” and that he regretted the “Russophobic obsession” of the United States.

The 38 individuals and entities newly designated by the Treasury Department were largely involved in efforts to try to knit Crimea and the breakaway Donbass region in eastern Ukraine more closely to Russia. A few were cheerleaders for the efforts.

Given that few of the individuals and entities have any known interactions outside Russia or areas of Ukraine under Russian influence, it is unclear that the sanctions will have an immediate effect on their work.

Various shell companies and banks used to extend Russian influence in the separatist regions of Donetsk and Luhansk were designated, as were officials who had suggested measures like using the Russian ruble in the region or issuing local passports that Russia would recognize.

In Crimea, the company insuring a $3 billion project to build a bridge linking the peninsula to the mainland was targeted, as well as a tourism project in the coastal city of Alushta.

Among the most intriguing sanctions were those involving a motorcycle gang, Mr. Putin’s chef and a shadowy company that supplies contract soldiers to Russian military efforts overseas.

A catering company owned by the chef, Evgeniy Prigozhin, who is sometimes called “the Kremlin’s chef” and who was the subject of sanctions in 2016, was added to the list. Among other contracts, the company, Concord Catering, supplies food to many of Moscow’s public schools, according to Russian news reports. Journalists have also reported that Mr. Prigozhin has funded a factory of so-called internet trolls who endorse Russia’s fans and harass its foes abroad.

Aleksandr Zaldostanov, an ardent Putin supporter who is the leader of the nationalistic Night Wolves motorcycle club and is known as the Surgeon, was previously the subject of sanctions. This time, two administrators and two organizations with ties to the Night Wolves, including the group’s Bike Center in Moscow, faced sanctions.

“A whole U.S. ministry is thinking about the Night Wolves,” Mr. Zaldostanov told the Russian news website gazeta.ru after the announcement.

The new sanctions were also directed against Dmitry Utkin, the founder of PMC Wagner, a private military contractor that the Treasury Department said had recruited soldiers to join separatists fighting in eastern Ukraine.

One Russian politician, Vladimir Dzhabarov, suggested that Moscow would weigh some manner of retaliation right away.

“We have to react calmly and, perhaps, to take a political decision on countermeasures,” Mr. Dzhabarov, the first deputy head of the foreign affairs committee in the upper house of the Russian Parliament, was quoted as saying by the Tass news agency.

As a candidate, Mr. Trump suggested that his presidency would herald a new era of improved relations between the United States and Russia, but the various investigations into possible collusion by his campaign have dampened those hopes. Instead, members of Congress have become increasingly resentful of Russian efforts to interfere in American politics.

Last week, Republicans and Democrats in the Senate voted for a measure that would bolster existing sanctions and allow Congress to thwart any presidential effort to curtail sanctions without congressional approval.

Hal Eren, a former Treasury official who worked in the department’s Office of Foreign Assets Control in the 1990s, said the Trump administration’s move on Tuesday was probably related to concerns about Congress trying to tie its hands.

“I think it was prompted by this contemplated legislation and meant as a way for the administration to say, ‘Look, we are doing something about this, and there is no need for this law,’” Mr. Eren said. “It’s a way to say that Trump is tough on Russia.”