Donald Trump's Russian oligarch-connected campaign manager may have resigned, but that doesn't put to rest the many questions regarding the GOP candidate's possible ties to Vladimir Putin and the Kremlin, Hillary Clinton's campaign said Friday.

"Paul Manafort's resignation is a clear admission that the disturbing connections between Donald Trump's team and pro-Kremlin elements in Russia and Ukraine are untenable," said Hillary For American campaign manager Robby Mook. "But this is not the end of the story. It's just the beginning. You can get rid of Manafort, but that doesn't end the odd bromance Trump has with Putin."

Questions about Trump's apparent connections to Russian forces have dogged the GOP candidate's campaign since its launch in June 2015.

Trump has stated his admiration for the Russian president repeatedly, calling him a "strong leader" and a "man so highly respected within his own country and beyond," and new reports suggest Trump's campaign manager, Paul Manafort, has some questionable ties to Russia.

Manafort, for his part, reportedly helped a pro-Russia Ukrainian political group quietly send $2.2 million to Washington lobbying firms, according to the Associated Press.

The former Trump campaign manager is also facing questions about his ties to pro-Kremlin forces, as pressure is mounting for him to answer for his consulting work to ousted Ukrainian President Viktor Yanukovych and others in Ukraine's pro-Russia Party of Regions.

Then there was the time in July when Trump suggested the Russians should help the U.S. find Clinton's unauthorized private State Department emails.

In short, Mook said Friday, there are questions.

"Trump still has to answer serious questions hovering over his campaign given his propensity to parrot Putin's talking points, the roster of advisers like Carter Page and Mike Flynn with deep ties to Russia, the recent Russian government hacking and disclosure of Democratic Party records, and reports that Breitbart published articles advocating pro-Kremlin positions on Ukraine," he said.

"It's also time for Donald Trump to come clean on his own business dealings with Russian interests, given recent news reports about his web of deep financial connections to business groups with Kremlin ties," he added.

This isn't the first time that the Clinton campaign has hit Trump over supposed ties to Russia.

The Democratic candidate's team released an attack ad Monday specifically questioning Trump's alleged ties to Putin.

"We don't know why Trump praises Putin," the Clinton video said Monday. "We don't know why they share foreign policies."

"We don't know why Trump's top advisers have ties to Putin," it added. "We don't know why Russia is trying to influence this election or why he is inviting them to."

Trump explained in a statement Friday morning that Manafort had left the campaign.

"This morning Paul Manafort offered, and I accepted, his resignation from the campaign," Trump said in a statement. "I am very appreciative for his great work in helping to get us where we are today, and in particular his work guiding us through the delegate and convention process."

The Republican candidate's son, Eric Trump, explained that the resignation came because the nominee didn't want Manafort's baggage "looming over the campaign."

"I think my father didn't want to be, you know, distracted by whatever things Paul was dealing with," he told the Fox Business Network's Maria Bartiromo.

"You know, Paul was amazing. He helped us get through the primary process, he helped us after the convention, he did a great job with the delegates," he added.