The development comes after a telephonic conversation between Stoltenberg and Ukraine's President Volodymyr Zelenskyy on Russia's war of aggression.
"Spoke with President @ZelenskyyUa on #Russia's war of aggression. At our #NATOSummit we will step up support for our close partner #Ukraine, now & for the longer term. #NATO Allies stand with you," the NATO secretary-general said in a tweet.
President Volodymyr Zelenskyy also addressed the leaders of the Group of Seven (G7) on Monday to press Western nations for accelerated sanctions on Russia.
The Ukraine-Russia conflict has been at the centre of the summit being held inside a century-old mountainside castle in Germany's Bavaria region.
During the summit, Prime Minister Narendra Modi made India's position clear on the Ukraine conflict and he reiterated that there must be an immediate end to the hostilities and a resolution should be reached by choosing the path of dialogue and diplomacy, said Foreign Secretary Vinay Kwatra.
PM Modi had also spoken with Ukrainian President Zelenskyy and expressed his deep anguish about the loss of life and property due to the ongoing conflict.
Leaders have decided on new steps to isolate Russia's economy, including a ban on new imports of Russian gold, and are pledging support for Zelenskyy as his country suffers setbacks in the east.
Moreover, US President Joe Biden announced that the group will impose new import bans on Russian gold as a punishment for Moscow's ongoing war in Ukraine.
The G7 leaders also held discussions on the impact of Russia's war on food and energy supplies including the global economy and said the bloc is determined to support Ukraine in producing and exporting grain, oil, and other agricultural products as well as to address the causes of the evolving global food crisis.
They called upon Russia to cease, without condition, its attacks on agricultural and transport infrastructure and enable free passage of agricultural shipping from Ukrainian ports in the Black Sea.
The leaders also agreed to further strengthen Ukraine's resilience by expanding cooperation in intelligence and information sharing, information security, as well as maritime security.
Condemning unprovoked and unjustifiable war, the leaders pledged USD 29.5 billion worth of support to Ukraine to help the country close its financing gap and continue ensuring the delivery of basic services to the Ukrainian people.