Washington (CNN) Migrants waiting at the US-Mexico border before mid-July should not be subject to new Trump administration asylum limits, a federal judge ruled Tuesday.

The departments of Justice and Homeland Security issued a rule in July prohibiting migrants who have resided or "transited en route" in a third country from seeking asylum in the US, therefore barring migrants -- many of whom are from Central American countries -- traveling through Mexico from being able to claim asylum and as a result, drastically limit who's eligible for asylum in the US.

Judge Cynthia Bashant of the Southern District of California ruled that the migrants who arrived prior to the July rule shouldn't fall subject to it because it didn't exist when they first arrived at the US-Mexico border.

The majority of migrants were from the Northern Triangle countries of Guatemala, Honduras, and El Salvador and had to travel through Mexico to reach the border. Upon arriving in the US, some turned themselves into the US Border Patrol and claimed asylum.

Despite arriving earlier in the year, some asylum seekers continued to wait in Mexico to be processed as a result of the administration's "metering" policy, which limits how many people can be processed through a legal port in a given day.

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