Australian Foreign Minister Stephen Smith said North Korea's missile capabilities were improving after the communist country test-fired seven ballistic missiles Saturday.

"We have seen improvements, regrettably, in their technology and their approach," he told the Nine Network on Sunday, emphasizing the latest missile tests were clearly a provocative act aimed at the U.S.

The launches on U.S. Independence Day appeared to be a poke at Washington as it moves to enforce U.N. as well as its own sanctions against the isolated regime for its May 25 nuclear test.

The ballistic missiles were likely capable of striking key government and military facilities in South Korea, a defense official said Sunday, amid growing concerns over Pyongyang's firepower.

The missile launches were a show of force that defied U.N. resolutions and drew international condemnation and concern.

The missiles appear to have traveled about 250 miles, meaning they could have reached almost any point in South Korea, an official at the South Korean Defense Ministry said on condition of anonymity, citing department policy.

The official said the exact details of the launches were still under investigation.

North and South Korea, which fought a 1950-53 war, still face off across the world's most heavily fortified border. The United States, South Korea's key ally, has 28,500 troops stationed in the country as a deterrent.

South Korea's Yonhap news agency — citing a South Korean government source it did not identify — reported that five of the seven ballistic missiles landed in one area, indicating their accuracy has improved.

Yonhap said two of the seven missiles launched are believed to be variants of Rodong missiles while the rest are believed to be upgraded versions of Scud-C missiles.

The modified Scud-C versions have a range of up to 370 miles, which could hit most of South Korea. Rodong missiles, meanwhile, have a range of up to 800 miles, putting most parts of Japan within striking distance.

Yonhap said, however, that the range of the Rodong missiles launched Saturday had been reduced apparently to improve accuracy.

The agency also said the North is believed to have deployed 200-300 Scud missiles and 200 Rodong missiles, with many of the Scud missiles positioned near the border with South Korea and capable of reaching the Seoul metropolitan area within four to six minutes. Yonhap said some experts thought the North has 500 to 600 Scuds.

Another South Korean Defense Ministry official said no signs of additional missile launches had been detected, but more were possible given North Korea warned ships to stay away from the area through July 10. He also spoke on condition of anonymity citing department policy.

North Korea's state news agency did not mention the launches, which drew condemnation from South Korea, Japan, Britain and France and expressions of concern from China and Russia — considered the countries closest to the North.

Chinese Foreign Ministry spokesman Qin Gang said in a statement that Beijing "hopes all parties will keep calm and restrained and jointly safeguard the overall peace and stability in this region."

The North has engaged in a series of acts this year widely seen as provocative. It fired a long-range rocket it said was a satellite in early April, and in late May it carried out its second underground nuclear test following the first in late 2006.

Last month, it appeared to be flouting new U.N. sanctions again when a ship believed to be carrying illegal weapons set sail. Yonhap said Sunday, however, that the boat, which turned around a week ago, is now headed toward Korean waters.

The country has also stoked tensions with rival South Korea and last month threatened "thousand-fold" military retaliation against the U.S. and its allies if provoked.