Rangers during the Dejima Refugee Crisis.
Section 4 (aka "The Rangers") is a special forces military unit in the JGSDF. It likely reports to military leadership that can extend to the Minister of Defense. Their missions and capabilities are similar to present-day United States Special Operations Command and its members all have identical cybernetic eyes.
Section 4 re-emerged in the TV series during the Dejima Refugee Crisis in an operation to recover a nuclear warhead from members of Section 9. The conflict between the units diffused when Batou revealed that he was once a Ranger himself, and both units returned the warhead to JGSDF. Unlike most modern Ranger units, the unit had female soldiers serving in the unit.