BENGHAZI, Libya, Jan 6 (Reuters) – Fires caused by clashes between Islamic State militants and guards near Libya's biggest oil ports have spread to four oil storage tanks that were still burning on Wednesday, a guards spokesman said. Ali al-Hassi said the Petroleum Facilities Guards were in control of Es Sider and Ras Lanuf ports, but that skirmishes continued. At least nine guards were killed and more than 40 injured in fighting around the perimeter of the area on Monday and Tuesday. Hassi said guards had recovered bodies of 30 Islamic State fighters, and had also captured two military tanks...