WASHINGTON (CNN) American opinions on the investigation into Russian interference in the 2016 US election appears hardened and driven by partisanship, according to a new CNN poll conducted by SSRS after a month rife with developments in the ongoing probe.

Overall, 6 in 10 say they see the investigation as a serious matter that should be fully investigated (58% say so), while around a third (36%) say it's mainly an effort to discredit Donald Trump's presidency. Those figures haven't changed significantly since February despite recent escalations in rhetoric from the President against the investigation and special counsel Robert Mueller specifically.

Since a February survey with similar findings, developments in the investigation into Russian interference in the 2016 election include news that Mueller's team is investigating Trump's financial dealings in Russia, upheaval on Trump's personal legal team, a report produced by Republicans on the House Intelligence Committee concluding that no collusion between Trump's campaign and Russia was found, a slew of tweets from the President directly criticizing the probe and Mueller himself and a statement from Trump's lawyer praying for the end of the investigation.

But neither views of Trump's handling of the probe nor those of Mueller's work have budged since February. The President continues to receive lower approval ratings for his handling of the Russia investigation than does Mueller (32% approve of Trump, 48% Mueller) -- both ratings are largely unchanged in the last month.

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