Launched a week after North Korea resumed missile tests following a three-month break, the projectiles, including from a multiple-launch rocket system (MLRS), flew up to 200km and reached 50km in altitude on Monday, South Korea's Joint Chiefs of Staff (JCS) said.
Hopes were raised for dialogue when North Korean leader Kim Jong Un met US President Donald Trump for a historic summit in Singapore in June 2018. But no significant progress has been made despite two more meetings between the leaders.
A US State Department spokeswoman said: "We continue to call on North Korea to avoid provocations, abide by obligations under United Nations Security Council Resolutions, and return to sustained and substantive negotiations to do its part to achieve complete denuclearisation."
China's foreign ministry called for all sides to use dialogue and show flexibility, saying the situation was "complex and sensitive".
"We also urge parties to make positive efforts to calm the situation for talks to continue, and to realise the denuclearisation and lasting peace in this region and the peninsula," spokesman Geng Shuang told a briefing.
The South Korean JCS expressed "strong regret" at the launches and South Korea's presidential Blue House called the drills "unhelpful" for Korean peninsula peace efforts.
Japanese Defence Minister Taro Kono said the projectiles appeared to be ballistic missiles and did not fall into Japan's exclusive economic zone.
Britain, Germany, France, Estonia and Belgium raised North Korea's recent launches at the UN Security Council on Thursday, calling them provocative actions that violated UN resolutions.
North Korea's foreign ministry criticised the European stand as "US-instigated reckless behaviour" and Kim's sister said the drills were not meant to threaten anyone.