The U.S. military says it has conducted two more airstrikes overnight on Taliban positions around a northern Afghan city seized by the insurgents this week.

U.S. Army spokesman, Col. Brian Tribus, says coalition advisers are at the scene Wednesday, "in the Kunduz area advising Afghan security forces."

Afghan forces have been massing around Kunduz for what is likely to be a protracted battle to retake the strategic city of 300,000 inhabitants.

Residents say fierce fighting for control of Kunduz's airport, a few kilometers (miles) outside the city, raged through the night before the Taliban retreated under fire. The residents spoke on condition of anonymity fearing for their safety.

The Taliban captured Kunduz on Monday — the first major city they have seized since the 2001 U.S.-led invasion ousted their regime.