Washington, Feb 23 (IANS): The Pentagon has said that even if everything goes according to plan, it will likely be months before construction on President Donald Trump's sought-after border wall can even start.

Trump recently declared a national emergency on the southern border, a move that in theory will allow his administration to tap and repurpose more than $3 billion in military construction funds to build sections of the wall, CNN reported.

Senior defence officials said on Friday that the Pentagon was currently awaiting a request from the Department of Homeland Security (DHS) to provide support for border wall construction.

While the Defence Secretary is required by law to make a determination that any military construction funds tapped for a border wall are being used to support the armed forces, the officials have said that there is no real criteria on which to make that determination.

"There are not formal criteria for that assessment," a senior defence official said on Friday, adding that Acting Secretary of Defence Pat Shanahan "will make a very deliberate decision per the law but the law does not proscribe explicit criteria".

The officials said that that assessment period alone could take weeks.

In addition, while the Trump administration has said that it intends to use some $2.5 billion from the Pentagon's counter-drug fund to help pay for the wall, the officials said that there is currently less than $80 million available for the wall in that account.

Therefore, the Trump administration would have to cut money from other defence accounts and reprogramme those funds into the counter-drug pot so that the money could be used for border fencing.