It is extremely rare for top North Korean officials to give interviews to foreign media, and particularly with Western news organisations.
Ri held firm to Pyongyang's longstanding position that the US drove his country to develop nuclear weapons as an act of self-defence.
At the same time, he suggested that suspending the military exercises with Seoul could open the door to talks and reduced tensions.
"If we continue on this path of confrontation, this will lead to very catastrophic results, not only for the two countries but for the whole entire world as well," he said, speaking through an interpreter.
"It is really crucial for the United States Government to withdraw its hostile policy against the DPRK [North Korea] and as an expression of this stop the military exercises, war exercises, in the Korean Peninsula. Then we will respond likewise."
The missile was fired from a submarine off North Korea's east coast, in the Sea of Japan, on Saturday night, the joint chiefs said. It flew for about 32km, well short of a submarine-launched ballistic missile's minimum range of 320km, Yonhap News Agency reported.
North Korea said last May that it had successfully test-fired a submarine-launched ballistic missile from under the sea, with the state news agency reporting that leader Kim Jong Un had ordered the test of the "world-level strategic weapon" and was present when it "soared into the sky from underwater".
North Korea also released photos of the event, including one that showed Kim on a boat holding binoculars as the rocket blasted out of the sea. But missile experts later said the launch was faked and the pictures had been doctored.
As Kim's regime prepares for a much-hyped communist Workers' Party congress early next month, analysts have been expecting Pyongyang to stage more provocations to give Kim more to crow about. A party congress has not been held since 1980, and Kim, 33, is expected to use the meeting to bolster his leadership legitimacy.
Tensions have run high since Kim ordered a nuclear test in January, swiftly followed by a long-range rocket launch that scientists say appeared to be part of an intercontinental ballistic missile programme.
4 things Ri Su Yong said
1 Proposal to the US
"Stop the nuclear war exercises in the Korean Peninsula, then we will also cease nuclear tests."
2 Nuclear dangers
"If we continue on this path of confrontation, this will lead to very catastrophic results, not only for the two countries but for the whole world as well."
3 Effect of sanctions
"If they believe that they can actually frustrate us with sanctions they are totally mistaken ... The more pressure you put on to something, the more emotionally you react to stand up against it. And this is important for the American policymakers to be aware of."
4 International pressure
"These big countries alone or together are telling us that we should calm down. For us this is like ... we should accept our death and refuse our right to sovereignty."
- AP, Washington Post, Bloomberg
