GOMA, CONGO — Fighting with M23 rebels in eastern Congo has left at least 13 peacekeepers and foreign soldiers dead, United Nations and army officials said Saturday. M23 has made significant territorial gains in recent weeks, encircling the eastern city of Goma, which has about 2 million people and is a regional hub for security and humanitarian efforts. The United Nations Security Council moved up an emergency meeting on the escalating violence to Sunday morning. Congo requested the meeting, which had originally been scheduled for Monday. On Saturday, Congo’s army said it fended off an M23 offensive toward Goma with