SEOUL  - North Korea fired short-range missiles into the sea off its eastern coast for the second time in a week Monday, prompting a warning from South Korea of “reckless provocation”.

The missile tests have clearly been timed to coincide with annual South Korea-US military exercises which kicked off a week ago and run until mid-April.

Two missiles were fired Monday and both flew around 500kminto the Sea of Japan, according to South Korea’s Defence Ministry. Four short-range Scud missiles were fired in similar fashion on Thursday.

Both tests were condemned by Seoul, which urged the North to cease all testing immediately and said it would consider calling for sanctions. “The North is taking a double-faced stance by making conciliatory gestures on one hand and pushing ahead with reckless provocation on the other,” said Defence Ministry spokesman Kim Min-Seok. The Scuds are at the longer edge of the short-range spectrum, with an estimated reach of 300-800 kilometres (185-500 miles) - capable of striking any target in the South.

It is not unusual for North Korea to carry out such tests, which often go unreported by South Korea. But Kim said the Scud firings were of particular concern.

“We believe that the North is testing various ballistic missiles with various ranges as a show of force to threaten us,” he said.

Washington initially played down Thursday’s firings, but later suggested they violated UN sanctions imposed on the North’s missile programme.

UN Security Council resolutions prohibit North Korea “from launching any ballistic missile, and this includes any Scud missile”, Pentagon spokesman Colonel Steven Warren said Friday.

Meanwhile, Japan and North Korean Red Cross and government officials met Monday for the first time since 2012 for what Pyongyang called a “productive” dialogue. After discussions in the northern Chinese city of Shenyang, the two sides agreed to hold more rounds of talks about the possible repatriation of the remains of Japanese nationals who died in the North during World War II.

The current meeting is set to last three days. “The two sides reached an understanding that it is necessary for them to meet continually in order to solve the question of the remains,” said the lead North Korean delegate Ri Ho-rim, according to Japan’s Jiji Press. “The talks were held in an earnest atmosphere and were productive,” Ri said.

Japan colonised Korea from 1910-45. Japanese counterpart Osamu Tasaka said “the two sides will hold another round of talks involving Red Cross and government officials”.

Diplomats from the two countries attended Monday’s talks along with the Red Cross officials.

“Both North Korean and Japanese sides reached common ground that we need to continue to meet in the future to resolve the issue of the remains of Japanese,” Ri was quoted by South Korea’s Yonhap news agency as saying.

“This round of talks becomes more important as government officials from the two nations attended.”

Officials from the two Red Cross societies last met in August 2012 and that meeting led to talks by government officials in November of that year.

They had planned to meet again in December 2012 but the plan was cancelled after Pyongyang announced its plan to launch a long-range missile.

One of the thorniest issues between Tokyo and Pyongyang is the fate of Japanese citizens who were kidnapped by North Korean agents in the 1970s and 80s to train its spies.

But it was unclear if the issue would be discussed in this week’s talks.