SAN JUAN, Puerto Rico — Julián Castro, in his first stop since announcing his presidential campaign, told Hispanic political leaders here Monday that President Donald Trump "failed the people of Puerto Rico" with his administration's response to Hurricane Maria and vowed to far better represent the U.S. territory if elected to replace him.

Castro, the former U.S. housing secretary and San Antonio mayor, spoke at the Latino Victory Fund summit two days after the the long-anticipated launch of his presidential campaign in his hometown. He said he chose Puerto Rico as his first post-announcement trip "because I want all the people of Puerto Rico to know that you count — that we respect you" — especially after Maria, which devastated the island in 2017.

"The administration failed to prepare for the hurricane," Castro said, "it failed to coordinate a swift response and it has failed in the recovery process as well."

"What's worse?" Castro asked before bringing up reports that the administration is now weighing whether to divert disaster relief funds to help fund Trump's long-sought border wall. "To do so is completely objectionable, immoral and should never happen."

The Latino Victory Fund meeting was the first of three stops that Castro was making Monday in Puerto Rico. After the summit, he visited two sites in the city to see hurricane recovery efforts, accompanied at the first stop by Carmen Yulín Cruz, the San Juan mayor and fierce Trump critic.

Before Castro’s arrival, a delegation of U.S. House Democrats was already visiting Puerto Rico to check on the Maria recovery and attend a winter retreat hosted by the political arm of the Congressional Hispanic Caucus. As Castro's swing through San Juan unfolded Monday morning, Trump criticized the House Democrats for making off to the sunny island amid the partial government shutdown spurred by his demands for border wall money.

"I've been here all weekend," Trump told reporters as he left the White House on Monday morning. "A lot of the Democrats were in Puerto Rico celebrating something — I don’t know, maybe they’re celebrating the shutdown."

Speaking with reporters before his stop with Cruz, Castro said he saw House Democrats doing "substantive work" on the island, noting they were set to meet later Monday with members of the Puerto Rican Legislative Assembly about the hurricane recovery. Then, Castro let it rip on Trump.

“I wish that the president would actually spend more time doing the job of being president instead of fighting people on Twitter and spending so much time golfing and not going to his first meeting until 11 a.m. in the morning," Castro said. "It’s amazing to me that we have a president who’s not even doing a part-time job, that is putting in less than hours than the average part-time worker."

"We need a president who’s dedicated to the job full time," Castro added.

Republicans returned fire at Castro, seeking to tie him to the rest of the island's Democratic visitors.

"It is disgusting that Julian Castro is trying to further his own political aspirations off of a natural disaster the administration has spent over a year addressing," Republican National Committee spokesman Steve Guest said in a statement. "Instead of focusing on the humanitarian crisis at our southern border, Castro chose to spend his weekend with Congressional Democrats who were partying at the beach with lobbyists."

Puerto Rico, which is home to over 3 million U.S. citizens, is not a typical first stop for White House hopefuls. Puerto Ricans cannot vote in the November presidential election but can participate in the nominating process. Last year, Democrats' Puerto Rico primary took place June 5.

Throughout the day, Castro leaned on his experience at the U.S. Department of Housing and Urban Development to empathize with Puerto Ricans still reeling from Maria. "This working is nothing new to me," he said at the Latino Victory Fund event, citing his trips as HUD secretary to states struck by natural disaster.

The crowd that Castro addressed at the Latino Victory Fund meeting included the first Latinas elected to Congress from Texas: Democratic U.S. Reps. Veronica Escobar of El Paso and Sylvia Garcia of Houston. Both were elected last year.