By Timour Azhari and Mohammed GhobariRIYADH/ADEN, July 24 (Reuters) - Yemen is edging towards the resumption of a more than decade-old frozen conflict, Yemeni officials, Western diplomats and analysts say, as attacks on Saudi infrastructure and shipping by Iran-aligned Houthis test the patience of the kingdom and the Yemeni government forces it backs.

A declared blockade of Saudi Arabia by Yemen's Houthi rebels has the potential to widen the Iran war.

As violence rises, both sides seek to increase their leverage without returning to war.