Russia's invasion of Ukraine has become a defining moment for some of the world's biggest tech companies, as their platforms have turned into major battlefields for a parallel information war and their data and services have become vital links in the conflict.

Over the last few days, various internet companies have had to grapple with how to wield that power, caught between demands by Ukrainian, Russian, European Union and the US.

Ukrainian leaders asked Apple, Meta and Google to restrict their services in Russia. Russian state-run media were barred from selling ads on their platforms by Meta and Google. The chief executive of Google spoke with European Union officials about how to counter Russian misinformation.

Telegram, a popular messaging app in Russia and Ukraine, threatened to shut down channels related to the war because of rampant misinformation. On Monday, Meta said it would restrict access to some of those outlets across the European Union to ward off war propaganda and that it would label all posts containing links to Russian state-affiliated media outlets.

The war is an opportunity for many companies, including Facebook, to rehabilitate their reputations after facing questions in recent years over privacy, market dominance and how they spread toxic and divisive content. They have a chance to show they can use their technology for good in a way not seen since the Arab Spring in 2011.

The tech companies have difficult decisions to make. If there is a mistake, it could lead to efforts in Europe and the United States to regulate their businesses or lead Russia to ban them.

Employees said that executives are making decisions about what to do. If they take some steps and not others, they might be accused of doing too little. Reducing too many services and information might cut off ordinary Russians from the digital conversations that can counteract state-run propaganda.

Yael Eisenstat, a fellow at the Berggruen, said that these companies want all the benefits of monopolizing the world's communications and not having to choose sides. Tech companies are in a no-win situation in the midst of an international crisis.

Traffic in Kyiv last week, days before Google stopped displaying traffic information inside Ukraine out of concerns that it could create a safety risks.Credit...Brendan Hoffman for The New York Times

Many of the companies have moved gingerly, said Marietje Schaake, a tech policy expert and former member of the European Parliament. Western policymakers had urged the companies to bar Russian state media from selling ads on their sites, but they did not.

The companies have taken additional steps. On Sunday, the Maps division stopped displaying traffic information inside of Ukranian out of concerns that it could create safety risks by showing where people were gathering. A pro-Kremlin influence campaign and a separate hacking campaign targeting its users were taken down by Facebook.

Users would be aware of the information sources if they were labeled with links to Russian state-affiliated media outlets. The company said users have linked to state-affiliated media about 45,000 times a day.

The measures were not enough according to Ms. Schaake, the international policy director at the Cyber Policy Center. She said that the companies should establish clear policies about their beliefs in human rights and democracy and block Russian propaganda outlets.

The interventions under huge pressure show what has not been done for a long time.

There would be negative consequences if the platforms were blocked in Russia.

They did not have a comment. It took its role in the conflict seriously. Facebook didn't comment.

Telegram's experience shows the competing pressures. The app is used in Russia and Ukraine to share information about the war. It has become a gathering place for war misinformation.

On Sunday, Telegram's founder posted to his more than 600,000 followers that he was considering blocking some war-related channels in Russia because they could cause more harm than good.

Users said they relied on Telegram for independent information. Less than an hour later, Mr. Durov changed his mind.

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What is the root of this invasion? Russia considers Ukraine to be within its sphere of influence, and it is worried that the country might join NATO or the European Union. The United States and Europe give financial and military aid to Ukraine.

Are these tensions starting now? The Russian military crossed into Ukrainian territory after the overthrow of their Russia-friendly president. There was a cease-fire in 2015, but fighting continues.

How has the Ukrainians responded? The state of emergency was declared after cyberattacks knocked out government institutions. Volodymyr Zelensky declared martial law after the attacks. The foreign minister called for the world to stop the attacks.

Many users asked us not to consider disabling Telegram channels for the period of the conflict, since we are the only source of information for them. Telegram didn't respond to the request for comment.

Two employees who were not authorized to speak publicly said that the situation at Inside Meta has been chaotic because of the amount of Russian misinformation on its apps. The two employees said that the Russian experts on Meta's security team have been working around the clock and communicating with companies about their findings.

The security team at Meta has debated whether to restrict Sputnik and Russia Today, two of Russia's largest state-run media sites, on its platforms or label their posts so they clearly state their source. According to a January report from the State Department, Russia Today and Sputnik are critical elements in the country's propaganda and misinformation.

The employees said that Meta executives resisted the moves, saying they would anger Russia. After war broke out, Meta decided to restrict access to Russia Today and Sputnik across the European Union.

There are two main types of war-related demands that tech companies face.

Russia wants them to censor social media posts and other information inside the country. Moscow has restricted access to social networking sites. On Monday, Russia demanded that Google block ads related to the war. That followed an order on Sunday to lift restrictions on pro-Kremlin media outlets, without saying how it would be enforced.

Western officials are pushing the companies to block Russian state media. On Monday, the leaders of six countries wrote to the internet companies to ask them to stop pro-Kremlin and official government accounts.

The letter said that the online platform providers and tech companies need to take a stand as authoritarian regimes seek to weaponize the openness of our societies to undermine peace and democracy.

The entrance to Russia Today in Moscow. Credit...Yuri Kadobnov/Agence France-Presse — Getty Images

The minister for digital policy in France met with the head of YouTube. On a call a day earlier, Mr. Pichai, the chief executive of the internet giant, and two European Union policymakers discussed how to counter Russian state-sponsored misinformation.

The vice prime minister of Ukraine wrote a letter to YouTube asking them to restrict access to their services in Russia. American policymakers have requested that Russian propaganda be stopped.

The power of the platforms is so clear that I don't think I've ever seen such a high-level political push for the companies.