Top American officials promised Ukrainian President Volodymyr Zelenskyy hundreds of millions of dollars in new aid during the highest-level U.S. visit to Ukraine since the start of the Russian invasion two months earlier, while Britain said Monday that Moscow has yet to achieve a significant breakthrough in its offensive in the eastern industrial heartland of the country. In meetings with Zelenskyy in Kyiv, U.S. Secretary of State Antony Blinken and U.S. Defense Secretary Lloyd Austin said the United States had approved a $165 million sale of ammunition for Ukraine’s war effort, along with more than $300 million in foreign military financing. The pledges came Sunday, the 60th day since the start of the invasion, as Ukraine pressed the West for more powerful weapons against Russia’s campaign in the Donbas region of eastern Ukraine, where Moscow’s forces sought to dislodge the last Ukrainian troops in the battered port of Mariupol. Britain’s Ministry of Defense said Monday that Ukrainian troops holed up in a steel plant in the strategic city were tying down Russian forces, and keeping them from being added to the offensive elsewhere in the Donbas. “Many Russian units remain fixed in the city and cannot be redeployed,” the ministry said in a statement posted on Twitter. “Ukraine’s defense of Mariupol has also exhausted many Russian units and reduced their combat effectiveness.” The ministry added that, so far, Russia has only made “minor advances in some areas since shifting its focus to fully occupying the Donbas.” Read: Zelenskyy meets top-level US delegation, gets aid promises “Without sufficient logistical and combat support enablers in place, Russia has yet to achieve a significant breakthrough,” the ministry said. On the diplomatic front, U.N. Secretary-General Antonio Guterres was scheduled to travel to Turkey on Monday and then Moscow and Kyiv. Zelenskyy said it was a mistake for Guterres to visit Russia before Ukraine. “Why? To hand over signals from Russia? What should we look for?” Zelenskyy said Saturday. “There are no corpses scattered on the Kutuzovsky Prospect,” he said, referring to one of Moscow’s main avenues. In a boost in support for Ukraine, French President Emmanuel Macron comfortably won a second term Sunday over far-right challenger Marine Le Pen, who had pledged to dilute France’s ties with the European Union and NATO. Le Pen had also spoken out against EU sanctions on Russian energy and had faced scrutiny during the campaign over her previous friendliness with the Kremlin. Macron’s victory was hailed by France’s allies in the EU as a reassuring sign of stability and continued support for Ukraine. France has played a leading role in international efforts to punish Russia with sanctions and is supplying weapons systems to Ukraine.