World leaders reacted to Donald Trump's victory in the US presidential election with offers to work with him tinged with anxiety over how he would deal with a host of problems, from the Middle East to an assertive Russia. Trump, who has no previous political or military experience, sent conciliatory signals after his upset of Democratic rival Hillary Clinton, pledging to seek common ground, not conflict, with the United States' allies. Ties between Washington and Moscow have become strained over the conflicts in Ukraine and Syria, and allegations of Russian cyber attacks featured in the US election campaign. "We heard the campaign statements of the future U.S. presidential candidate about the restoration of relations between Russia and the United States," Putin said. Palestinian President Mahmoud Abbas also congratulated Trump, but analysts said his rule may be profoundly negative for Palestinian aspirations.