July 20 (Reuters) - Yemen's Iran-aligned Houthis will impose a maritime blockade on Saudi Arabia, they said on Monday, further throttling a global energy market already greatly restricted by Iran's closure of the Strait of Hormuz.This is why it matters and what it means for the Iran war and the global energy crisis:HOW BIG IS THE RISK TO GLOBAL ENERGY MARKETS?It is not clear how the Houthis would carry out a maritime blockade of Saudi Arabia, its northern neighbour along the Red Sea coast, or whether it would include a return to attacks on shipping.

The move could increase pressure on already-strained global energy markets.

In a statement, the Houthis military spokesperson Yahya Saree said the group would enforce the blockade against its "criminal Saudi enemy" effective immediately.