TOA BAJA, Puerto Rico -- Republican Party members in Puerto Rico awarded all 20 delegates at stake Sunday to Arizona Sen. John McCain, who has vowed to help resolve Washington's complicated relationship with the U.S. Caribbean territory.

The delegates each will cast one vote at the Republican National Convention in September, joined by three local members of the Republican National Committee who also have pledged to back McCain as party delegates.

McCain swept all 38 GOP delegates awarded in U.S. territories over the weekend, moving him closer to Republican nomination for president. He also picked up endorsements from two unpledged delegates, giving him a total of 998. His rival, former Arkansas Gov. Mike Huckabee trails with 254 delegates.

It will take 1,191 delegates to secure the Republican nomination.

On Saturday, McCain picked up all nine delegates awarded by the GOP in American Samoa, as well as the nine GOP delegates from the U.S. Commonwealth of the Northern Mariana Islands.

In a letter to Luis Fortuno, Puerto Rico's nonvoting congressional delegate and a superdelegate, McCain pledged to support a process that would enable Puerto Ricans to decide if they want to remain a commonwealth, become a state or an independent nation.

"The people of Puerto Rico deserve a process of self-determination and a congressionally defined referendum that gives them a fair and unambiguous choice among status options," McCain wrote. "That is one of the many important things that we will accomplish together."

Puerto Ricans are U.S. citizens but cannot vote for president, and their representation in Congress is restricted to a single nonvoting member.