WASHINGTON (AP) — Two U.S. officials say the Biden administration is expected to announce an additional $275 million in military aid for Ukraine on Friday. It comes as Kyiv struggles to hold off advances by Russian troops in the Kharkiv region. This will be the fourth installment of military aid for Ukraine since Congress passed a long-delayed foreign aid bill late last month. The U.S. has pledged to keep weapons flowing regularly to Ukraine to get them to the front lines as quickly as possible. The officials say the package includes high mobility artillery rocket systems, or HIMARS, as well 155 mm and 105 mm high-demand artillery rounds.