At a virtual address to German Christian Social Union members on Wednesday, Stoltenberg said 2021 presents an important opportunity to re-energize transatlantic relations and strengthen the bond between North America and Europe.
"Any attempt to divide Europe and North America will not only weaken the transatlantic bond or weaken NATO, but also divide Europe, so we need to stand together, North America and Europe, and I really count on Germany playing [a] key role in these efforts," Stoltenberg said.
He also said 2021 will be a "pivotal year" in terms of NATO's continued presence in Afghanistan.
"Next month, NATO's defense ministers will meet, and they need to decide whether to remain, whether to stay in Afghanistan with our military presence, and then risk being engaged in a prolonged military presence in Afghanistan, or whether to leave, but then risk that Afghanistan once again becomes a safe haven for international terrorists," Stoltenberg said.
According to Stoltenberg, NATO Defense Ministers will assess the future of NATO's mission in Afghanistan next month.
Stoltenberg also referenced the pending expiration of the new START arms reduction treaty, which limits strategic nuclear arms held by the United States and Russia -- and is scheduled to expire in February.
"NATO has always been on the forefront of arms control fighting for strong and balanced arms control and disarmament," Stoltenberg said. "We need to make sure that we ... don't end up in a situation where there is no agreement regulating the number of nuclear warheads," Stoltenberg said.
In December, NATO released a statement opposing the United Nations' new treaty banning nuclear weapons, saying it is "at odds with the existing non-proliferation and disarmament architecture."
Stoltenberg did not address the latter question, but said he had already called President-elect Joe Biden to congratulate him and had invited him to this year's NATO summit.
"I'm just confident that when we have a new president in place after the inauguration on the 20th of January, NATO will continue to work with the United States, and with the new president," Stoltenberg said.
NATO's press release about the address and transcript were published Wednesday afternoon, before a violent mob stormed the Capitol building in Washington, D.C., to disrupt Congressional certification of Electoral College votes.
Stoltenberg has since joined other world leaders in condemning the violence.
"Shocking scenes in Washington, D.C.," Stoltenberg wrote on Twitter. "The outcome of this democratic election must be respected."