WASHINGTON - A US federal judge on Thursday blocked President Donald Trump's administration from attempting to dismantle the Department of Education, marking the first instance that a federal judge declared the administration's extensive changes to the department unlawful.

Judge Myong Joun from the US District Court for the District of Massachusetts, who was appointed by former president Joe Biden, issued a preliminary injunction prohibiting the administration from dismissing half of the department's employees.

It also prevents the department from shifting the management of federal student loans to the Small Business Administration.

Trump has long criticized the department, arguing that despite significant federal investment in education, the quality of education has not met expectations.

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Citing low proficiency in reading and math among students in US elementary, middle and high schools, Trump said that the department is "doing us no good" and his administration is returning education to the states.

In March, he signed an executive order to formally begin the process of dismantling the department.

The department previously initiated a large-scale layoff. According to earlier US media reports, the department, which originally had 4,000 employees, would cut nearly half of its workforce.

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The establishment and dismantling of federal agencies generally require Congressional approval through legislation.