ATLANTIC OCEAN, ABOARD THE AMPHIBIOUS ASSUALT SHIP IWO JIMA — An additional 150 Marines and four MV-22 Ospreys flew aboard here Monday afternoon, adding to the 1,700 troops and four MH-60 Seahawks headed to help Haiti after a ferocious hurricane.

Six days since Hurricane Matthew carved a swath of destruction through southern Haiti, U.S. Southern Command stood up Joint Task Force Matthew at the Port au Prince airport. The amphibious transport dock Mesa Verde arrived in Haiti with 300 Marines on Sunday. Iwo Jima will arrive later in the week.

Video: This is how 1,850 U.S. sailors, Marines are preparing to help hurricane-stricken Haiti

Military Times is aboard the USS Iwo Jima with 1,200 sailors and 650 Marines who are getting ready to provide relief efforts in Haiti after Hurricane Matthew swept through the island.

The recently added Ospreys and Marines are part of the 24

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Marine Expeditionary Unit’s aviation wing, which had been embarked on the carrier George Washington. But through the weekend the USAID-led mission came into better focus as assessment teams surveyed the wreckage left in Matthew’s wake and the Marines began delivering relief supplies.

On Sunday alone, Marines conducted nine sorties, delivering 50,240 pounds of supplies to USAID's Office of Foreign Disaster Relief and non-governmental organizations teams on the ground, according to Marine Corps officials.

The GW was slated to provide assistance to the Bahamas, but that government determined the help wasn’t necessary. Leaders then shifted many of the assets and equipment to the Iwo Jima.

Hurricane Matthew made landfall Oct. 4 and is blamed for more than 1,000 deaths in Haiti, according to a Reuters tally. A cholera epidemic has begun to spread in the nation’s devastated southern region.

Aid efforts have been hampered by flooding, downed trees and wrecked bridges. About 1.4 million Haitians are in need of humanitarian assistance, according to the U.N. Office for the Coordination of Humanitarian Affairs.

Within 36 hours of Matthew’s landfall, SOUTHCOM had boots on the ground. Task Force Matthew grew within days to about 170 military personnel and nine helicopters.The Mesa Verde’s crew of about 375, along with 300 Marines, brought the number to nearly 850. The Iwo's arrival will almost triple the number of U.S. troops involved in relief efforts in Haiti.

Mesa Verde will depart once Iwo arrives on station, but will transfer its 300 Marines and the Expeditionary Strike Group 2 staff over to Iwo first.

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MEU was called into action in the middle of workups for an early 2017 deployment. For most Marines here, it’s their first deployment.

"I was excited to do this," said Lance Cpl. Zachary Younts, 20, diesel engine mechanic. "I hate just sitting in the shop fixing diesels all day, this is a change of pace."

The Marines were given a warning order the day before the hurricane on Oct. 3 that they could deploy within days to Haiti. The first Marines were on board Mesa Verde from Camp Lejeune, North Carolina, on Oct. 5. The 24

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MEU was called on again to load up on Iwo Jima on Oct. 6 and embarked two days later.

"The Marine Expeditionary Unit, it’s all about crisis response," said Lt. Col. Christopher Hafer, who runs the 24

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MEU’s logistics operation. "Whatever that mission is, we want to make sure we have a responsive force."

Sailors from Iwo Jima were initially sortied from Mayport, Florida, to avoid the hurricane on Oct. 5. They learned they would be tasked for Haiti relief shortly after getting underway.

A Navy survey team, which will assess channels used to bring equipment from Iwo to the beach in Haiti, were ordered to Norfolk from Mississippi on Friday. The team and their tactical jet skis drove through the night to embark the ship before getting underway Saturday.

The trip to Haiti has been a rough one for Iwo Jima. On Saturday and Sunday, the ship had to dodge the hurricane and contend with 20-foot-plus seas that tossed around the 850-foot-long gator, making daily routine difficult for the crew and embarked Marines. It also precluded any flight ops.

By Monday the seas had calmed and Iwo was headed to Haiti unhindered.

Marine Corps Times reporter Matthew L. Schehl contributed to this report.