 U.S. preparing for Iranian retaliatory strike, American troops face constant threat. The White House has warned of the substantial threat faced by U.S. troops in Iraq and Syria amid a stream of threats issued by Iranian leadership in response to a suspected Israeli airstrike that killed several Iranian personnel last week near its embassy in Damascus. Addressing the warnings at a virtual press briefing, National Security Council Strategic Communicator's Coordinator John Kirby declined to go into specific intelligence matters but reiterated President Joe Biden's assurance that the Israeli government could count on the United States' support for any self-defense needs against threats directly by Iran to Israel, threats that Iran has made public and discussed preparations for potential risks to U.S. personnel as well. Our own people, not just our troops, but our diplomatic personnel as well in Iraq and Syria are under constant threat, Kirby said. We take that seriously and we take the appropriate force protection measures we need to as the threat changes to make sure that they can protect themselves and that has not changed. That will not change. We're continuing to do that, but we take the threat to our people in our own facilities seriously and we know that those groups, many of the groups that conduct those kind of attacks, are supported, funded, resourced by the Islamic Revolutionary Guard Corps. The Islamic Revolutionary Guard Corps is one of three primary branches of the Iranian armed forces, along with the army which, like the Islamic Revolutionary Guard Corps, includes ground, naval, air and missile branches and the law enforcement force. Branded a terrorist organization by the U.S. in 2019, the IRGC and its elite CUDS force conduct operations abroad and coordinate with an international coalition of militias known as the Axis of Resistance, including in Iran and Syria. Such groups have targeted Israel and U.S. troops since the war in the Gaza Strip erupted six months ago between the Israel, the Israel Defense Forces and the Palestinian Hamas movement and Israel has targeted Iran-aligned units in Syria as part of a years-long semi-covert campaign. Moscow says Biden-linked Ukrainian firm connected to terror attacks in Russia, White House responds. Washington has insisted there was no reason to search for any other potential suspects besides Islamic State. After Moscow said it was looking at certain Western companies and government officials as part of an investigation into the funding of a string of terrorist attacks in Russia, the Russian Investigative Committee has established that the funds flowing through commercial organizations, including the oil and gas conglomerate, Burisma Holdings, operating in Ukraine, have been used in recent years to carry out terrorist attacks in Russia. Spokeswoman Svetlana Petrenko said, beside last month's Kroger City Hall attack, the investigation is looking at other terrorist acts, including the assassinations of prominent public figures and the bombing of the Nord Stream gas pipelines. Speaking to journalists, National Security Advisor Jake Sullivan focused on reinforcing Washington's narrative on the Kroger's attack while dismissing any other potential leads and other incidents. It's nonsense, Jake Sullivan stated. Russia knows it was Islamic State who committed the attack in Moscow. We know it was Islamic State who committed the attack in Moscow. He warned Russia of an impending terrorist attack in Moscow and all the rest of this is noise. Russia launched a probe into allegations that Ukraine and its Western backers are involved in terrorist activities on Russian soil after a referral by several lawmakers in the wake of the March 22 attack. The investigation has allegedly established that at least some of the terrorist funding had been funneled through Ukrainian companies, including the notorious Burisma Holdings, former employers of US President Joe Biden's son Hunter. Washington issued a public warning about an imminent attack in Russia in early March weeks before the Kroger's city assault. The US refuses to allow any discussion of potential Ukrainian involvement in last month's terrorist attack near Moscow because Washington is ultimately accountable for Kiev's actions. The secretary of the Russian Security Council Nikolai Patrushev said last week.