The US missile deployment, which comes a day after North Korea tested four ballistic missiles, has led to diplomatic tension between China and South Korea.
Ukraine began two days of missile tests on Thursday, avoiding the air space over Crimea which could have provoked a confrontation with Russia.
The US military has condemned a ‘‘failed’‘ North Korean test launch of an intermediate ballistic missile near the northwestern city of Kusong.
Russia has raised tensions once again in Syria with it deploying for the first time an S300 surface-to-air missile system to its Tartus naval base in Syria.
Hundreds of South Koreans have had their heads shaved in protest over a government decision to install a US manufactured anti-missile defence unit.
North Korea has fired three ballistic missiles into the sea off its east coast, according to South Korea’s military.