NATO today reappointed Jens Stoltenberg as secretary general to serve until 2020, as the alliance undergoes its biggest revamp since the Cold War to counter the perceived threat posed by Russia.

The former Norwegian prime minister, who took over in October 2014, will pilot the alliance into its next summit in Brussels in July with the North Korean nuclear crisis and US President Donald Trump’s apparent ambivalence towards NATO looming large.

The alliance is making ambitious reforms to its command structures that aim to make NATO fit for the challenges of warfare in the 21st century — particularly the threat from cyber tactics and hybrid warfare.

The North Atlantic Council, NATO’s main political decision-making body, said the 29 alliance members had agreed to extend Stoltenberg’s mandate to September 30, 2020.

“Allies congratulate the secretary general and have full confidence in his ability to continue his dedicated work to advance NATO’s adaptation to the security challenges of the 21st century,” the council said in a statement.

Former Norwegian prime minister Stoltenberg, 58, who took the job in October 2014, wrote on Twitter that he was “honoured and grateful” to have his mandate extended.

“Looking forward to continue working together to strengthen the Alliance and keep our citizens safe,” Stoltenberg wrote.