A senior defense official said on Tuesday that a convoy of Russian vehicles heading south towards eastern Ukraine appeared to be moving slowly and would likely be forced to get stuck on the roads due to the spring weather. The official told reporters that it was not clear how fast the convoy was moving, but said it was not heading towards the east front at “strong speed”. RUSSIA INVASES UKRAINE: LIVE UPDATES A dog is seen in the middle of a street as Ukrainian army soldiers take part in a military broom to search for possible remnants of Russian troops after leaving villages on the outskirts of Kiev, Ukraine, Friday, April 1, 2022. (AP Photo / Rodrigo Abd ) Pentagon spokesman John Kirby said Monday that the Russian convoy appeared to be an attempt to “step up its efforts in Donbas” – but could not confirm what the Russian forces were bringing with them except a “mix of personnel” and vehicles. . The escort is located about 37 miles north of the town of Izyum, which is about 16 miles from the Donbas regional border. “I do not know his final destination,” a senior defense official told reporters on Tuesday, noting that the escort was moving south. “But I would rely on that in the spring if they had to stay on the paved roads. They live on highways and boulevards. They do not go off-road here.” UKRAINE DOES NOT UNDERSTAND WHAT IS NEEDED TO “END THE WAR EARLY”, ENDS FROM “TIME” AND “LIFE”: ZELENSKYY Map depicting Ukraine, Russia, Crimea, the Donbas region held by pro-Russian forces and neighboring countries. Ian Jopson, Fox Digital (Fox News) Officials have long warned that hot weather will make it harder for Russia to make ground invasions as heavily armored vehicles move more slowly in muddy conditions. A senior U.S. defense official said Ukrainian troops did not appear to be attacking the convoy, although previous attempts by Russia to push a convoy south of Kyiv proved unsuccessful earlier this year. Russia is estimated to have retained just over 80 percent of its fighting force since the Moscow invasion 47 days ago. However, officials have also warned that Russia could seek to recruit up to 60,000 more troops to help with its deadly campaign. The United States and NATO said last week that Russia would seek to strike at eastern Ukraine in a “major offensive” after failing to occupy the capital, Kiev. Ukrainian President Voldymyr Zelenskyy warned on Tuesday that his forces still lacked what they needed to end the Russian invasion and again urged allied states to send jets to Kyiv and more armored vehicles. The United States has pledged to send Switchblade drones to Ukraine armed with tank-destroying warheads, but Washington has continued to refuse to send real warplanes. Ukrainian soldiers climb into a fighter jet outside Kyiv, Ukraine, Saturday, April 2, 2022. As Russian forces withdraw from the Ukrainian capital, retreating troops create a “catastrophic” situation for civilians, leaving mines around, leaving mines around. equipment and “even the bodies of those killed,” President Volodymyr Zelenskyy warned on Saturday. CLICK HERE TO RECEIVE THE FOX NEWS APPLICATION A senior defense official told reporters that a “significant” quantity of the first 100 Switchblade drones has been delivered to Ukraine and more are expected in the near future. The official said the US is in constant contact with Ukraine to get what it needs in a timely manner.