Russia-Ukraine updates: Putin says 'certain positive movements' in negotiations

U.S. President Joe Biden called the parents of Trevor Reed, a former U.S. Marine who has been detained in Russia for nearly three years and whose case has gotten renewed attention amid the Ukraine-Russia conflict.

The president spoke to Joey and Paula Reed after an event in Fort Worth, Texas, on Tuesday, according to the White House.

On the call, the president reiterated his commitment to doing everything he can to bring their son home, to staying in close touch with them through his national security team and to finding a time to meet in person, the White House said.

A Reed family spokesperson also confirmed to ABC News that Biden called them to apologize for not being able to stop and meet them in person.

The family says they have been asking to meet with the president for several months to help free Reed, a Texan who they say has been denied treatment for suspected tuberculosis, and specifically asked to meet the president in Texas on Tuesday but were denied.

Reed and another former Marine, Paul Whelan, have spent years in Russian custody on charges that their families and American officials say were fabricated by Russia in order to seize them as bargaining chips.

-ABC News' Sarah Kolinovsky and Conor Finnegan

Ukrainian President Volodymyr Zelenskyy thanked U.S. President Joe Biden for additional sanctions taken against Russia on Tuesday, saying they will "significantly weaken the occupiers."

The new measures include a ban on imports of oil, petroleum products, gas and coal from Russia. U.S. citizens are also now prohibited from investing in Russia's fuel and energy sector.

"A ban on oil imports to the United States will weaken the terrorist state economically, politically and ideologically, because it is about freedom -- about the future, about where the world will move," Zelenskyy said, adding that he is "personally grateful" to Biden.

Zelenskyy also expressed gratitude to U.K. Prime Minister Boris Johnson for instating a similar ban, describing Johnson as "a man of his word, a sincere friend of Ukraine."

-ABC News' Christine Theodorou

Even with a series of harsh measures already taken on Russia, including a ban on Russian imports, the sanctioning of Russia’s central bank and the enactment of export controls, the U.S. could enact even tighter sanctions, several experts told ABC News.

The U.S. could push other countries to make commitments to decrease their reliance on Russian energy -- which it and the U.K. are already beginning to do -- and to increase their own production of oil and gas to lower the high energy prices Americans and Europeans are starting to face — and it could also get Saudi Arabia, Venezuela and others to increase their exports.

Other current sanctions the U.S. could tighten include imposing "full-blocking" sanctions, the harshest possible financial sanctions, on Sberbank, Russia’s largest bank. The U.S. has already done this for several other banks but has only put limited restrictions on Sberbank in order to limit the impact on the ordinary Russians who use the bank.

The U.S. could also put additional secondary sanctions on banks, put more restrictions on Russian goods, keep pursuing oligarchs and other Russian elites and sanction other Russian sectors such as minerals, chemicals, and coal.

The sanctions the West has already imposed have devastated the Russian economy at a rapid clip. They will continue to compound and inflict more pain on the Russian economy as they continue to play out, the experts said.

-ABC News' Ben Gittleson

The Coca-Cola Company and PepsiCo have suspended business in Russia, the companies announced Tuesday.

"Our hearts are with the people who are enduring unconscionable effects from these tragic events in Ukraine," the release states. "We will continue to monitor and assess the situation as circumstances evolve."

Pepsi, which has ben operating in Russia for more than 60 years, "must stay true to the humanitarian aspect of our business," CEO Ramon Laguarta wrote in a letter to PepsiCo associates.

"Our first priority continues to be the safety and security of our fellow Ukrainian associates," Laguarta said. "We suspended operations in Ukraine to enable our associates to seek safety for themselves and their families, and our dedicated crisis teams in the sector and region continue to closely monitor developments in real time."

Pepsi will also continue to provide aid to assist Ukrainians refugees in neighboring countries, including donating milk and refrigerators to relief organizations, and we’re ramping up production of foods and beverages in neighboring countries to meet the increased need, Laguarta said.

-ABC News' Will Gretsky