BEIRUT, Aug 31 (Reuters) - Lebanon"s parliament speaker Nabih Berri urged the country"s top politicians on Tuesday to form a government no later than this week. In a televised speech, Berri urged politicians to put aside their differences in order to save the country from economic collapse. Lebanon, which is suffering a deep economic crisis, has been run by a caretaker administration since the government resigned more than a year ago. Prime minister-designate Najib Mikati, the third to attempt to form a government, said last week there were big hurdles ahead. In his remarks on Tuesday, Berri said political factions should not hinder the formation of a government by demanding blocking minorities in the new cabinet. President Michel Aoun has denied accusations that he is demanding a third of cabinet seats for his allies, which would allow them to veto cabinet decisions.