SEOUL, Korea, Republic Of -- South Koreans' stomachs are the latest front in the standoff with North Korea.

South Koreans have been told not to eat at North Korea's restaurants around the world, although such visits aren't illegal, the South's Foreign Ministry said Wednesday.

Most of the restaurants are in China, and Chinese and other nationalities frequent them more than South Koreans do, so analysts see little impact. But the move is symbolic of a tougher stance from the South since North Korea's nuclear test last month and its recent rocket launch, which many outsiders see as a banned test of ballistic missile technology.

Washington and Seoul have been calling for more stringent financial and trade sanctions against Pyongyang. President Park Geun-hye has taken a much harder line than during past standoffs with the North, closing a jointly run factory park that the South believes helped finance Pyongyang's nuclear weapons and ballistic missiles program. Park on Tuesday also warned of "regime collapse" in the North, formerly a taboo subject in the South, which cherishes the notion of an eventual peaceful reunification on the peninsula that was divided at the end of World War II by the Soviet Union and the United States.

North Korea runs about 130 restaurants in other countries -- about 100 in China and the others in Russia, Southeast and South Asia, according to a South Korean National Intelligence Service official who didn't want to be named, citing office rules. South Korean officials wouldn't say how many South Koreans visit those restaurants or how much money the businesses generate for North Korea, reportedly more than $100 million annually.

Restaurants such as Beijing's Okryukwan, known for its cold buckwheat noodles and grilled marinated beef, have been popular among some South Korean leisure and business travellers.