(Reuters) - Russia wants a long-term peace deal over Ukraine that tackles what it regards as the root causes of the conflict and not a quick U.S.-backed ceasefire followed by a swift restart of fighting, a senior Russian diplomat told the RIA news agency.

In an interview released on Monday, the third anniversary of tens of thousands of Russian troops crossing into Ukraine at the orders of President Vladimir Putin, Russian Deputy Foreign Minister Sergei Ryabkov said Moscow was after a Ukraine deal that stood the test of time.

"We can recognise with sufficient confidence the desire of the American side to move towards a quick ceasefire," RIA cited Ryabkov as saying.

"But ... a ceasefire without a long-term settlement is the path to a swift resumption of fighting and a resumption of the conflict with even more serious consequences, including consequences for Russian-American relations. We do not want this.

"We need to find a long-term solution, which, in turn, must necessarily include an element of overcoming the root causes of what has been happening in and around Ukraine," said Ryabkov.

Russia-U.S. talks held in Riyadh last week, which Moscow has said agreed to work on restoring bilateral ties and preparing for Ukraine talks, did not offer greater clarity about President Donald Trump's peace plan for Ukraine, Ryabkov said.

He repeated Moscow's stance that it had no choice but to launch what it calls its "special military operation" in Ukraine - something Ukraine and the West call a brutal colonial-style war of conquest - because of what he said was the NATO alliance's "unrestrained" eastwards expansion.

He also complained about what he called the trampling of the rights of the Russian-speaking population in Ukraine, repeating an allegation which Kyiv denies.

(Reporting by Andrew Osborn in London and Lidia Kelly in Melbourne; Editing by Sonali Paul/Andrew Osborn)