WASHINGTON — President Obama broadened U.S. sanctions against Russia on Thursday, targeting additional senior Russian officials and a large bank, while threatening to impose new sanctions on “key sectors of the Russian economy” if the country continues to escalate its incursion into Ukraine.

On the trade front, senior administration officials, who spoke on the condition of anonymity to reporters Thursday, said there are growing concerns about reports on the ground that Russia has imposed an illegal trade embargo against Ukrainian goods imports.

It was the first hint that Russia might be resorting to trade retaliation against the intensifying pressure coming from the international community following Russia’s annexation of Crimea from Ukraine.

American and European businesses that export to Russia or have investments in the country are becoming increasingly concerned about the rising political tensions. The U.S. has not indicated trade sanctions as a possible deterrent to date, but companies are more concerned that Russia might target specific U.S. or EU industries’ exports.

Obama condemned what he claimed was an “illegal” referendum and move by Russia to annex Crimea as he announced sanctions against several senior high level Russian government officials (20 in total) many of them considered to be in the inner circle of Russian President Vladimir Putin. Bank Rossiya was also sanctioned.

Obama also signed an executive order on Thursday that broadens the U.S. authority to impose sanctions on Russian industries if Russia invades any other regions of Ukraine.

“The world is watching with grave concern as Russia has positioned its military in a way that could lead to further incursions into southern and eastern Ukraine,” Obama said.  For this reason, we’ve been working closely with our European partners to develop more severe actions that could be taken if Russia continues to escalate the situation.”

“As part of that process, I signed a new executive order today that gives us the authority to impose sanctions not just on individuals but on key sectors of the Russian economy,” Obama added. “This is not our preferred outcome.  These sanctions would not only have a significant impact on the Russian economy, but could also be disruptive to the global economy. However, Russia must know that further escalation will only isolate it further from the international community.”

The key sectors targeted by the U.S. for potential sanctions include financial services, energy, metals and mining, defense and engineering, according to senior administration officials.

Obama plans to travel to Europe next week where he’ll meet with the Group of Seven leaders to discuss whether to pursue more drastic sanctions against Russia as well as aid for Ukraine.

While the U.S. stands on alert for any new military action by Russia, it is also concerned about trade retaliation from Russia.

“We are not only launching military pressure…, we are also launching political and economic pressure,” a senior administration official said. “Again, these sanctions have the potential to escalate… In particular, we are deeply concerned today the Russians have appeared to close the border to Ukrainian goods entering Russia, effectively having imposed a trade embargo. This is unacceptable under their WTO [World Trade Organization] obligations. So we are watching that.”