In 1954, West Germany opened an embassy in Asunción. That same year, Alfredo Stroessner became President of Paraguay. Stroessner was of German origin on his father's side and ruled Paraguay for 35 years. His time in office became known as "El Stronato". Stroessner kept close political ties with West Germany and paid several visits to the country, but relations between West Germany and Stroessner soured when the West German government pressured him to stop sheltering Nazi war criminals in Paraguay. In 1964, the West German government asked Stroessner to extradite Mengele but Stroessner angrily refused and would not strip him of his citizenship either. In February 1989, Stroessner was ousted from power and relations between West Germany and Paraguay resumed once again.