Japanese Prime Minister Taro Aso says the international community needs to put strong pressure on North Korea under a new United Nations sanctions regime.
The Japanese leader said it is necessary that North Korea understand that it will not benefit from what he called "further acts of provocation."
Mr. Aso spoke in Tokyo Tuesday, where his foreign minister met with U.N. Secretary-General Ban Ki-moon for talks on North Korea and other issues.
The Japanese prime minister is scheduled to meet with Mr. Ban on Wednesday.
The U.N. secretary-general called on U.N. member states to implement a new resolution that tightens sanctions against North Korea.
On Monday, Japanese police arrested three men for allegedly attempting to export a magnetic measuring device to Burma that could be used to develop missiles.
The company that was trying to export the device is based in China, but is believed to have links to North Korea's government.
The international community is stepping up efforts to monitor North Korea's trading practices and its proliferation of missile technology.
A U.S. Navy destroyer is tracking a North Korean vessel, the Kang Nam, which some South Korean media reports say is heading to Burma via Singapore.
The ship belongs to a fleet that U.S. officials say has been used in the past to transport weapons.
Also Monday, South Korea's defense minister, Lee Sang-hee, said North Korea appears to be pushing forward with a uranium enrichment program, which he said far easier to hide than the North's current plutonium-based program.
North Korea has ample supplies of natural uranium, and it could conduct an enrichment program in underground or undisclosed facilities, away from the view of U.S. spy satellites.
Earlier this month, after the United Nations placed more sanctions on North Korea for carrying out its second nuclear test in May, Pyongyang said it would start enriching uranium.
The U.S. State Department's new coordinator for North Korea sanctions, Philip Goldberg, is traveling to China on Tuesday on his first foreign trip in that role. Goldberg's mission is to persuade China, a North Korean ally and trading partner, to enforce the sanctions rigorously.
Some information for this report was provided by AFP, AP and Reuters.