Russia on Thursday issued another threat to the US, saying it would cross a “red line” if Washington supplied Ukraine with longer-range missiles. Moscow “reserves the right to defend its territory,” Foreign Minister Maria Zakharova said during a briefing, according to Reuters. The US has already provided 16 High Mobility Artillery Missile Systems (HIMARS) to Ukraine, with more on the way. They have a range of about 50 miles. A launch truck fires the High Mobility Artillery Missile System (HIMARS) produced by Lockheed Martin during combat training in the high desert of the Yakima Training Center in Washington state, May 23, 2011. (Tony Overman/The Olympian via AP/File ) Ukraine has called on the US and other nations to help it further as it pushes the front line further east and retakes territory in the northern Kharkiv region. ZELENSKY’S HOMETOWN IN UKRAINE FLOODS AFTER RUSSIAN CRUISE MISSILE LAUNCHES BREAK DAM Kyiv has argued for months that it needs longer-range missile capabilities, such as the Army Tactical Missile System (ATACMS), which has a range of about 185 miles, to deal with its roughly 1,500-mile battle front. A US Army Tactical Missile System (ATACMS) launches a missile into the East Sea during a joint South Korea-US missile exercise. (South Korean Ministry of Defense via Getty Images) RUSSIA IN UKRAINE SEES COLLABORATION OF COMMAND AND CONTROL AS TROOPS WITHDRAW IN ‘PANIC’: UK INTELLIGENCE Longer-range missile systems could also prove beneficial to Ukrainian forces. Ukrainian President Volodymyr Zelenskyy has said his troops will not stop resisting Russia until all of Ukraine, including Crimea, which Russia has occupied since 2014, is liberated. “If Washington decides to supply longer-range missiles to Kyiv, then it will cross the red line and become a direct part of the conflict,” Zakharova said. The White House has repeatedly said that while it promises to continue providing military and humanitarian aid to Ukraine, it is not willing to send some missile systems like the ATACMS. The U.S. Army Tactical Missile System (ATACMS) launches a missile into the East Sea during a joint South Korea-U.S. missile exercise. (South Korean Ministry of Defense via Getty Images) CLICK HERE TO GET THE FOX NEWS APP The Biden administration has cited concerns about sparking World War III, which Ukraine has scoffed at, saying it has no intention of firing on Russian soil. The fight for Crimea will likely prove to be an uphill battle, as Russia has considered it as claimed land since its invasion nearly a decade ago. Caitlin McFall is a reporter for Fox News Digital. She can be reached at [email protected] or @ctlnmcfall on Twitter.