US President Joe Biden has cast doubt on Ukraine's chances of quickly joining Nato ahead of a major summit in Lithuania this week. "I don’t think it’s ready for membership in Nato," he told CNN<i> </i>in an interview aired on Sunday, as he prepared to fly to London. He said joining the bloc required countries to “meet all the qualifications, from democratisation to a whole range of other issues.” On Tuesday and Wednesday, Nato's 31 member nations will meet in Vilnius amid high security as the war in Ukraine rages just a few hundred kilometres away. While squabbling among Nato members is not uncommon, any signs of division in the current climate will be perceived as a weakness by Russia. On Sunday, German diplomatic sources told the UK's <i>Telegraph </i>newspaper that they were prepared to block Volodymyr Zelenskyy's attempts to join amid fears it could drag the alliance into armed conflict with Russia. A Nato source suggested German Chancellor <a href="https://www.thenationalnews.com/world/europe/2023/05/02/olaf-scholz-and-rishi-sunak-urged-to-support-climate-finance-reform/" target="_blank">Olaf Scholz</a> and his team would use the annual summit to press for a collective focus on security assurances, rather than membership proposals, to help Kyiv defend itself without becoming a member. “Berlin is standoffish at the prospect of offering immediate membership,” the source told <i>The Telegraph</i>. “It wants a process and time to develop guarantees to essentially block membership.” The insider added that Germany was trying to avert a scenario that would see President Vladimir Putin “potentially test Article 5”. The clause stipulates if a Nato member is attacked, all of its fellow signatories will consider it an attack on themselves and must come to its defence. Amid division over Washington’s decision to arm Kyiv with cluster munitions, the allies also appear to be poles apart on how to respond to <a href="https://www.thenationalnews.com/world/europe/2023/07/07/zelenskyy-to-meet-turkeys-erdogan-to-push-ukraines-nato-goals/" target="_blank">President Zelenskyy</a>’s calls for accession. _________________________________ _________________________________ Germany is not alone in its reluctance to give Mr Zelenskyy a seat at the table in the near future. The topic poses one of the largest challenges facing Nato. Some argue that admitting Ukraine would fulfil a promise made year ago and be an important step to deter Russian aggression in Eastern Europe. But others are sceptical, making the case that such a move could be viewed by Moscow as a provocation. Douglas Lute, who served as US ambassador to Nato under former American president Barack Obama, said: “Any fissure, any lack of solidarity provides an opportunity for those who would oppose the alliance." Russian President Vladimir Putin is eager to exploit divisions as he struggles to gain ground in Ukraine and faces political challenges at home, including the aftermath of a brief revolt by the Wagner mercenary group. “You don’t want to present any openings,” Mr Lute said. “You don’t want to present any gaps or seams.”