MINSK, Belarus (AP) — At least two Ukrainian troops have been killed in the past 24 hours in renewed fighting in eastern Ukraine, officials said Wednesday.

Fighting between Russia-backed separatists and Ukrainian government troops has killed more than 9,600 people since the conflict began in April 2014. A 2015 cease-fire deal did not completely stop fighting but did lower its intensity.

Andriy Lysenko, the ministry's spokesman, said in a statement that in addition to the deaths, one Ukrainian soldier has been held captive while eight more have been injured in the past 24 hours south of the rebel stronghold of Donetsk.

At least seven Ukrainian troops have been killed in fighting since Sunday with dozens more injured and shell-shocked, authorities said. Kiev says the Russia-backed rebels have been trying to push through government positions outside the town of Svitlodarsk, south of Donetsk. The rebels have denied these claims and accused the government of attacking them.

U.S. State Department spokesman John Kirby told reporters in Washington that the United States is deeply concerned about the recent spike in violence in eastern Ukraine. Kirby called on Russia to "exercise its considerable influence over the separatists to put a stop to the violence" and give monitors from the Organization for Security and Cooperation in Europe full access to rebel-held areas.

Ukrainian analysts described fighting earlier this week as the worst since this summer.

Clashes at Svitlodarsk "could provoke a new spike of tensions and an escalation of the conflict in the east," Mykola Sungurovsky, a Kiev-based military expert at the Razumkov Center, told The Associated Press.