Esper announced in a statement released by the Pentagon on Thursday that America will send one Patriot missile system battery, four Sentinel radars and approximately 200 support personnel to Saudi Arabia, Xinhua news agency reported.
The move will "augment the kingdom's air and missile defence of critical military and civilian infrastructure," according to the statement.
Esper added in the statement that he has also approved to put additional US forces "on prepare to deploy order," including two more Patriot batteries and a Terminal High Altitude Area Defence system (THAAD).
The Pentagon chief's announcement came one week after US President Donald Trump approved sending more US forces to the Gulf which are "defensive in nature" and will be "primarily focused on air and missile defence."
Washington has blamed Iran for being responsible for the drone attacks on oil production facilities in eastern Saudi Arabia earlier this month, a claim that has been strongly denied by Tehran.
The United States has kept piling up pressure on Iran through its "maximum pressure campaign." On Thursday, Trump announced a presidential proclamation barring the senior Iranian government officials and their family members from entering into America.
On Wednesday, Iranian President Hassan Rouhani ruled out negotiations with the United States unless the latter lifts sanctions on his country first, further dampening the hope of a meeting between him and Trump on the sidelines of the United Nations General Assembly this week.
( With inputs from IANS )