If U.S. President Donald Trump was inclined to be tentative when raising the issue of election meddling when he meets with Russian President Vladimir Putin on Monday, the indictment Friday of 12 Russian intelligence officers over hacking in 2016 has made that approach a much harder sell.

A federal grand jury alleged that officers of Russia's military intelligence agency, the GRU, secretly monitored computers and stole data from the campaign of Trump's Democratic rival, Hillary Clinton.

The charges put an even greater spotlight on Trump's treatment of Putin, who has denied making efforts to intervene in the election, which the Republican unexpectedly won.