North Korea fired seven rockets into the East Sea in another show of force against the ongoing South Korea-U.S. military drills on Tuesday, a day after it launched two ballistic missiles into the sea.

Starting at 4:17 p.m., the North launched four rockets from the Hodo peninsula near the eastern coastal city of Wonsan, Seoul’s Defense Ministry said. The rockets, which appeared to be “KN-09” rockets, flew some 155 kilometers.

Earlier in the morning, around 6 a.m., the North had fired three shorter-range rockets, which traveled some 50 km, the ministry said.

Pyongyang’s provocative move came as Seoul and Washington criticized it for violating a series of U.N. Security Council resolutions by launching a total of six short-range ballistic missiles on Monday and last Thursday.

Washington appears increasingly discontented over North Korea’s ballistic missile launches on Monday, criticizing them as a violation of UNSC resolutions and calling for restraint.

When Pyongyang launched four missiles with a range of some 300 km last Thursday, the U.S.’ response was subdued. But with this week’s launch of two missiles with a range of some 500 km, it increased its criticism, speaking of “provocative actions.”

“We urge North Korea to refrain from provocative actions that aggravate tensions and instead focus on its international obligations and commitments,” State Department spokesperson Jen Psaki told reporters in Washington on Monday. “Scud missile launches are a violation of these U.N. Security Council resolutions.”

Despite the criticism, Washington is unlikely to refer the case to the U.N. Security Council for additional punitive actions, given all the domestic and international issues that it has to deal with, analysts said.

The U.S. is currently swamped with a host of more urgent issues such as Russia’s military intervention in Ukraine’s Crimea region, the Iranian nuclear problem, the Syrian civil war and domestic financial woes.

At the UNSC, Washington has rarely taken issue with Pyongyang’s launches of short-range missiles.

It has so far brought to the U.N. the cases of the North launching Rodong missiles with a range of 1,300 km and Musudan missiles with a range of over 3,000 km as those missiles could threaten its allies and mainland.

The North’s Scud missiles can target the South and U.S. troops on the peninsula, while Rodong missiles are capable of striking Japan. Musudan missiles can travel over the Pacific Ocean to Guam.

The longest-range North Korean missile under development is the Taepodong-2 missile, which is thought to have a range of some 6,700 km, far enough to reach the U.S. mainland.

Seoul and Washington believe that this week’s missile launches contravened U.N. Security Council Resolutions 1874, 2087 and 2094, which ban Pyongyang from conducting ballistic missile launches.

The resolutions were adopted after Pyongyang conducted three underground nuclear tests and test-launched a series of long-range missiles in defiance of international warnings.

North Korea’s firing of the missiles is seen as a show of force against South Korea and the U.S., which are conducting their joint military exercises. Pyongyang has denounced the allied drills as a rehearsal for a war of invasion.

Analysts largely agree that Pyongyang is unlikely to seriously escalate tensions given that it has sought to improve ties with Seoul and other neighboring countries in an apparent bid to secure economic assistance.

For the Kim Jong-un regime, shoring up the moribund economy is at the top of the state priorities as public loyalty to the dynastic ruler could wane due to worsening poverty.

By Song Sang-ho (sshluck@heraldcorp.com)