U.S. President Donald Trump has renewed his criticism of the decision to leave American military equipment in Afghanistan, calling it a “foolish” move that undermined years of investment in rebuilding efforts of the former Afghan Army.

At a joint press conference with Saudi Crown Prince Mohammed bin Salman, Trump said that during his first term, his administration strengthened the U.S. military “to a level never seen before.” He argued, however, that some of that equipment was “unnecessarily left behind” during the U.S. withdrawal from Afghanistan.

“Under the Trump administration, America became great again and open for business,” he said. “We rebuilt our military stronger than ever. Unfortunately, and foolishly, a small amount of that equipment was given away in Afghanistan. Compared to what we built, it was minor — but it should never have happened. Now we are rebuilding at a level we’ve never done before, and we’re sending large amounts to our allies as well.”

Trump has frequently criticized the manner in which U.S. forces exited Afghanistan, insisting that the withdrawal was poorly executed and that billions of dollars’ worth of equipment should not have been left behind.

The Islamic Emirate of Afghanistan has maintained that all military equipment found within the country after the collapse of the former government now belongs to the Afghan people and “will not be returned to anyone.”

After the U.S. withdrawal and the Islamic Emirate’s return to power, a substantial amount of American-supplied equipment previously used by Afghan National Army forces came under the new authorities’ control. U.S. media reports have estimated that nearly $7 billion worth of American military equipment remained in Afghanistan.

Afghan analysts within the country argue that the equipment constitutes part of Afghanistan’s national assets and cannot be reclaimed by any foreign government.