According to Stoltenberg, NATO has intensified monitoring the development of nuclear weapons and missiles by North Korea as well as the situation in the region.
"We have stepped up our analysis, our monitoring of the situation in the region of the development of nuclear weapons and missiles in North Korea. We are enhancing our cooperation with partners in the region, especially South Korea and Japan. We have had several meetings with our partners in NATO over the last months," Stoltenberg said.
He also welcomed the approval by the UN Security Council of new sanctions against North Korea.
On Monday, the UN Security Council unanimously adopted its toughest resolution yet against North Korea over its latest nuclear test and repeated missile launches. Resolution 2375 restricts oil exports to Pyongyang, bans imports of textile products from the Asian nation as well as the country's access to gas liquids among other restrictions.
Asked if North Korea was capable of attacking the United States, Stoltenberg said: "They are in the process of developing those kinds of capabilities. And that's exactly why this is of great concern, not only for the United States and NATO but for the whole international community. This is a threat to international peace and security. It's a global threat, and it has to be met with a global response."
"Therefore I welcome the decision by the UN on economic sanctions. It is important that those sanctions are fully implemented by all nations. The North Korean missile and nuclear weapon program is a blatant violation of several UN Security Council resolutions, and it's destabilizing the whole region and increasing tensions," he said.
NATO-Russia Council, Relations With Moscow
According to Stoltenberg, Chairman of the NATO Military Committee Gen. Petr Pavel and Russian General Staff Chief Gen. Valery Gerasimov discussed the development of military contacts at their personal meeting.
The first meeting between top military officials of NATO and Russia since the termination of NATO-Russia practical cooperation took place on September 7 in Baku.
"I welcome the meeting between the Chairman of our Military Committee, General Petr Pavel, and General Gerasimov, because that's an important part of our military lines of communications. And for NATO, it is important to maintain a political dialogue with Russia, and also keep the political lines of communications open," Stoltenberg said.
"I will not go into the details of the meeting, but they addressed issues related to military transparency and predictability to make sure that we avoid any incidents or accidents when we now have more tensions or more activity, more military presence along our borders," he said.
The NATO chief also blamed Russia for never opening up any military exercises since the end of the Cold War under the Vienna Document on confidence and security building measures.
"Russia has not opened any exercise since the end of the Cold War for mandatory observation under the Vienna Document, and the Vienna Document is the international agreement regulating transparency and the observation of military exercises," Stoltenberg said.
"And therefore we call on Russia to abide by the Vienna Document, but also to help to modernize the Vienna Document. Because there are so many loopholes, and there is obvious potential for improving the Vienna Document," he said.
NATO is studying the possibility of holding a new meeting of the NATO-Russia Council (NRC), Stoltenberg stated.
"We just had a meeting in July. But after the summer break, we have now started to look into the possibility of a new meeting of the NATO-Russia Council. NATO has suspended the practical cooperation, but we think it is important to maintain political dialogue, and military lines of communications," Stoltenberg said.
NATO has not discussed the possibility of lowering the level of Russian representation at the alliance, but sees the presence of the Russian ambassador to NATO in Brussels as useful, Jens Stoltenberg said.
In August, the newspaper Izvestia, citing sources in the Russian Foreign Ministry, reported that Moscow was considering the possibility of lowering the level of representation at the North Atlantic alliance to charge d'affaires ad interim. The report said this could happen after Russian envoy to NATO Alexander Grushko left his post. Such measures, according to the newspaper, were due to the fact that NATO was not seeking constructive dialogue.
"That has not been an issue discussed in any NATO meetings. Russia decides, of course, what kind of representation, what level Russia wants to be represented at, at NATO. But I think it has proven useful to have a Russian ambassador here. Grushko is an experienced ambassador. And even though there are disagreements, I think it's important that we have an organized dialogue and contact, as we have with the Russian presence here at NATO," Stoltenberg said.
He underlined that NATO would keep seeking better relations with Russia.
"Russia is NATO's neighbor. Russia's there to stay. And NATO doesn't want a new Cold War. We don't want a new arms race. We will continue to strive for improved relationships with Russia," Stoltenberg said.
Stoltenberg also noted that he planned to meet with Russian Foreign Minister Sergey Lavrov on the sidelines of the UN General Assembly and discuss, among other things, the situation around Ukraine.
"I will also meet Foreign Minister Lavrov at the UN General Assembly next week, and that is also part of the dialogue which has been a part of NATO-Russia relations for many, many years, but which I regard as even more important now because we are living in a more unpredictable and more challenging time regarding security," Stoltenberg said.
The Russian Foreign Ministry has commented on issue earlier in the day, saying that "Various meetings have been planned, including a meeting with the NATO secretary general," the ministry's Information and Press Department said.
The UNGA General Debate will take place in New York from September 19-25.
Ukrainian Crisis, Situation in Donbass
Jens Stoltenberg commented on the possibility of Ukraine's NATO membership, saying that no Action Plan (MAP) for Ukraine is currently on the alliance's agenda.
"There is no MAP on the agenda. What we are doing now is that we are supporting Ukraine to implement reforms, to modernize its armed forces, to strengthen its defense and security institutions, and that's our focus," Stoltenberg said.
He mentioned in connection with proposals to send peacekeepers to Donbass to protect the OSCE mission in the region that he welcomed any proposals that help to implement the Minsk agreements.
"I regret that we have seen so many violations of the ceasefire, problems with implementing the Minsk Agreements. At the same time, I welcome that we have seen some new proposals on the table, and I welcome any proposal which can help to implement the Minsk Agreements to end the fighting, the bloodshed in eastern Ukraine and make sure that we are able to implement the political solution," Stoltenberg said.
Turkey and S-400 Deal
Commenting on reports on Turkey's purchase of Russia's S-400 air defense missile systems, Stoltenberg said that each NATO member state makes its own decision on the purchase of weapons.
"It's up to each and every individual ally to decide what kind of equipment they acquire. This is a national Turkish decision. What is important for NATO is that our different systems are working together, that we have what we call interoperability. For this system, there has been no request for integrating it into the NATO air defense system. So that has not been on the table," Stoltenberg said.