Active duty members of the US Coast Guard did not receive their first paycheck of the year Tuesday as a result of the ongoing partial US government shutdown, the head of the Coast Guard announced this week.

"Today you will not be receiving your regularly scheduled mid-month paycheck," Adm. Karl Schultz wrote in a letter sent to active duty members, which was published on social media.

"To the best of my knowledge, this marks the first time in our nation's history that service members in a US Armed Force have not been paid during a lapse in government appropriations," Schultz added.

The Coast Guard is the only military service that falls under the US Department of Homeland Security (DHS), and is thus the sole service impacted by the shutdown, which began on December 22 when Congress refused to allocate $5.6 billion in the next year's budget to build a wall on the US-Mexican border.

Some 42,000 active-duty Coast Guard service members will remain unpaid until a budget deal or another agreement is reached.

While some government employees, such as Federal Aviation Administration workers, have been furloughed, the Coast Guard has continued its operations throughout the longest US federal government shutdown in history.

"Your senior leadership, including [DHS] Secretary [Kirstjen] Nielsen, remains fully engaged, and we will maintain a steady flow of communications to keep you updated on developments," Schultz wrote in his letter. "I recognize the anxiety and uncertainty this situation places on you and your family, and we are working closely with service organizations on your behalf."

Schulz also added that the United Service Automobile Association has donated $15 million to the Coast Guard Mutual Assistance fund, which will be distributed to military and civilian workforce members requiring assistance.

"The strength of our Service has, and always will be, our people," Schultz added in his letter, reminding members of their ability to overcome hardship.

"You have proven time and again the ability to rise above adversity. Stay the course, stand the watch and serve with pride. You are not, and will not, be forgotten," he wrote.