SEOUL (AFP) - After North Korea announced on Thursday it has approved plans for nuclear strikes on US targets, here are some facts on the relative conventional strengths of the three militaries present on the Korean peninsula.

The figures are taken from the London-based International Institute of Strategic Studies' annual global "Military Balance" report, 2011.

North Korea's annual defence spending as of 2008 was estimated at US$8.2 billion, or 22-24 per cent of GDP, while South Korea's as of 2012 was US$30.8 billion, or 2.7 per cent of GDP.

South Korea is protected by the US "nuclear" umbrella, while North Korea, which conducted its third nuclear test in February, claims a potent nuclear weapons capability.

The range of North Korean missiles, and its ability to manufacture and deliver working nuclear warheads, are a matter of dispute.

Most experts think it is not yet capable of mounting a nuclear device on a ballistic missile capable of striking US bases or territory.