By Laila Bassam BEIRUT, June 4 (Reuters) - Leba**n's interior minister extended the term of the head of the internal security forces on Thursday without securing cross-party agreement, avoiding a vacuum at the top of a major security agency but triggering a political row. Government in Leba**n has been largely paralysed by the repercussions of the war in Syria. Leba**n's fractious politicians have been unable to make any major decisions, including important appointments in security agencies.