SEOUL, July 22 (Reuters) - North Korea fired several cruise missiles toward the sea to the west of the Korean Peninsula, the South Korean military said on Saturday.

This would be North Korea's latest missile launch since it fired two ballistic missiles on Wednesday, as Pyongyang and Washington step up displays of military force in a standoff over the isolated country's nuclear weapons and missile programmes.

A number of cruise missiles launched since around 4 a.m. Saturday local time (1900 Friday GMT) were detected, South Korea's Joint Chiefs of Staff said.

On Wednesday, North Korea fired missiles hours after a U.S. nuclear-armed ballistic missile submarine (SSBN) surfaced for a rare visit to South Korea.

North Korea also warned on Thursday that deployment of U.S. aircraft carriers, bombers or missile submarines in South Korea could meet criteria for its use of nuclear weapons.