Ignacio Ibanez, Spain's secretary of state for foreign affairs, and Antony Blinken, the US deputy secretary of state, will sign the agreement in Washington.
"Given the worsening situation in the areas close to our territory, we have reached an agreement with the United States to expand its capabilities in Moron and make them permanent," Spain's Defense Minister Pedro Morenes said Wednesday, explaining the necessity of the deal in the local parliament, quoted by local media.
The agreement was to be signed on June 1, but United States Secretary of State John Kerry had to cancel his visit to Spain due to an injury sustained in a cycling accident in the French Alps.
After the 2012 deadly attack on the US mission in Benghazi, the United States asked Spain to make the Moron base available for to use as a rapid response staging area to emergency situations in Africa.
Initially, Madrid allowed 550 US marines to be based at Moron. In 2014, Spain extended the mandate and agreed to increase the total number of US personnel to 850.
