Brazil has argued the visit could have been used to raise suspicions about the electoral system's reliability ahead of October's vote, which the US state department rejects.
The US president's latest comments come weeks after he offered Kyiv the right to make the missiles.
President Donald Trump had blamed "sick" vandals, and a former Olympian had been charged, but prosecutors now say contractors caused the damage.
The US president's comments come after cyber attacks on Minnesota's water systems earlier this week, with US media indicating Iran could be behind it.
The suspect was working as an intern in Nato's Supreme Headquarters Allied Powers (Shape) Europe in Mons, Belgium.
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Brazil's president confirms two US government officials were denied visas over election interference fears
Brazil has argued the visit could have been used to raise suspicions about the electoral system's reliability ahead of October's vote, which the US state department rejects.
Trump now 'not sure' about letting Ukraine build Patriot missiles
The US president's latest comments come weeks after he offered Kyiv the right to make the missiles.
Trump administration drops Reflecting Pool vandalism charge and admits 'botched' repairs
President Donald Trump had blamed "sick" vandals, and a former Olympian had been charged, but prosecutors now say contractors caused the damage.
Minnesota not Iran to blame for state's water issues, says Trump
The US president's comments come after cyber attacks on Minnesota's water systems earlier this week, with US media indicating Iran could be behind it.
Belgium says a Canadian intern is suspected of spying at Nato. Here's what we know
The suspect was working as an intern in Nato's Supreme Headquarters Allied Powers (Shape) Europe in Mons, Belgium.