WASHINGTON — The Pentagon has eased restrictions that allowed a small number of private American defense contractors to work in Ukraine and help repair and maintain equipment, U.S. officials said Friday.

Officials said the contractors will be away from the front lines and will not take part in hostilities during Russia’s invasion. The ministry is currently seeking proposals, said officials who spoke on condition of anonymity to discuss internal decisions.

Ukraine has been purchasing American arms and equipment worth billions of dollars in the last two years; These include a number of advanced systems. For much of this time, U.S. and allied troops were using phones and tablets to communicate with Ukrainian forces in encrypted chat rooms, providing real-time maintenance recommendations.

Officials said the Pentagon let the contractors go because repairs to some equipment, including F-16 fighter jets and air defense systems, required high-tech expertise. They said the use of contractors would ensure rapid repair of the weapons so that Ukrainian forces could continue to use them in combat.

The decision expands the footprint of U.S. government contractors working in Ukraine. The State Department has already contracted U.S. companies to work inside the country, including on the energy grid. In addition, a number of American companies have workers in Ukraine under contract with the Kyiv government.

Officials said companies will be responsible for the safety of their employees.