Moscow - Russian President Vladimir Putin's spokesperson voiced hope for a constructive dialogue with President Donald Trump's administration in comments broadcast on Saturday, but warned that differences will remain.Dmitry Peskov said in an interview with state Rossiya television that it would be an "illusion" to expect that US-Russian relations would be completely free of disagreements."Successful development of bilateral ties will depend on our ability to solve these differences through dialogue," Peskov said. He added that Putin will call Trump soon to congratulate him.Nuclear parityTrump has promised to mend ties with Moscow badly strained over the Ukrainian crisis, the war in Syria and allegations of Russian meddling in the US elections and his victory has elated Russian political elites.Peskov, however, pointed at the challenges posed by the intricacy of nuclear arms control, the complexity of the situation in Syria and other issues.While Russia supports prospective nuclear arms cuts, they should be proportional and not upset the nuclear parity between Russia and the US, which "plays a critical role in ensuring global stability and security," Peskov said.He noted that different composition of Russian and US nuclear forces is a factor that needs to be carefully considered in negotiations.Asked to comment on Trump's recent interview with the Times of London in which he indicated that he could end sanctions imposed on Russia in the aftermath of the 2014 annexation of Crimea in return for a nuclear arms reduction deal, Peskov said that the two issues are hard to link.Opposed involvementPeskov emphasised the US role in settling the nearly six-year conflict in Syria, where Trump has offered to pool efforts with Russia in fighting the Islamic State group."It's quite obvious that it's impossible to constructively solve the Syrian problem without the US' participation," he said.Russia already has invited Trump's administration to attend talks between Syrian government and opposition groups in the Kazakhstan capital on Monday. Russia brokered the talks together with Turkey and Iran, but Tehran has opposed the US' involvement in them.