The nation has been attempting a successful launch of the Musudan missile which has an approximate range of between 2,500 and 4,000 kilometres.
The North's latest provocation followed an announcement by the United States and South Korea on Wednesday to further strengthen their security alliance with the start of talks on an "extended deterrence" against a nuclear North Korea.
"I assured the Minister of our commitment, the Unites States' commitment, to defend South Korea through a robust, combined defense posture and through extended deterrence, including the USA nuclear umbrella, conventional strike and missile defense capabilities", Kerry added. The North regularly threatens to destroy the South and its main ally, the United States.
This year alone, which happens to be the 10th year since its first nuclear test, the North conducted two nuclear tests, fired 23 ballistic missiles, and even reprocessed plutonium.
"Let me be clear", Kerry told reporters after meetings Wednesday in Washington with Foreign Minister Yun Byung-se and other South Korean officials.
Kerry also reiterated Washington's stance that it will not accept North Korea as a nuclear state, warning the continued pursuit of nuclear and missile programs will put the North under more stringent sanctions.
North Korean officials also claim their missiles now have the ability to reach the U.S. Pacific coast. "The United States will do whatever is necessary to defend ourselves and to honor the security commitment we have made to our allies", Kerry said.
The Defense secretary noted that "growing trilateral cooperation" among South Korea, Japan and the U.S.
Mr Kerry reiterated the USA will deploy "as soon as possible" a Terminal High Altitude Area Defence (THAAD), a missile defence system meant to protect South Korea and the almost 30,000 U.S. forces based there.
Such a weapon could threaten military installations on Guam and the US nuclear bombers that play a key role in deterrence on the Korean Peninsula.
Hours before the launch, the US and South Korea agreed to strengthen military and diplomatic efforts against the North.
The U.S. and China, which is the North's traditional ally and main trading partner, are now negotiating at the U.N. Security Council on tightening sanctions in response to the September 9 nuclear test.
The exercise took place in the Yellow Sea between mainland China and the Korean Peninsula, waters off South Korea's southern island of Jeju, and in the Sea of Japan to the east.
South Korean President Park Geun-Hye said the North was "blatantly threatening" the entire region, while her foreign ministry denounced Pyongyang's "manic obsession" with nuclear bombs and missile.