KYIV, Ukraine (AP) — Talks to stop the fighting in Ukraine have resumed as another attempt to rescue civilians from the besieged port city of Mariupol broke down. Also, Russia is accusing the Ukrainians of launching a cross-border helicopter attack on a fuel depot. A Kremlin spokesman says the incident on Russian soil could undermine Friday’s negotiations. Ukraine is denying responsibility for the attack. Meanwhile, Russia continued withdrawing some of its ground forces from areas around Kyiv. The Kremlin said earlier this week that it would reduce military activity near the Ukrainian capital and the northern city of Chernihiv to promote trust at the bargaining table.