Mayotte
claimed by Comoros

Mexico
prolonged drought, population growth, and outmoded practices
and infrastructure in the border region have strained water-sharing
arrangements with the US; the US has stepped up efforts to stem
nationals from Mexico, Central America, and other parts of the world
from illegally crossing the border with Mexico

Micronesia, Federated States of
none

Midway Islands
none

Moldova
Moldova and Ukraine have established joint customs posts to
monitor transit through Moldova's break-away Transnistria Region
which remains under OSCE supervision

Monaco
none

Mongolia
none

Montserrat
none

Morocco
claims and administers Western Sahara whose sovereignty
remains unresolved - UN-administered cease-fire has remained in
effect since September 1991, but attempts to hold a referendum have
failed and parties thus far have rejected all brokered proposals;
Morocco protests Spain's control over the coastal enclaves of Ceuta,
Melilla, and Penon de Velez de la Gomera, the islands of Penon de
Alhucemas and Islas Chafarinas, and surrounding waters; discussions
have not progressed on a comprehensive maritime delimitation setting
limits on exploration and refugee interdiction since Morocco's 2002
rejection of Spain's unilateral designation of a median line from
the Canary Islands; Morocco serves as one of the primary launching
areas of illegal migration into Spain from North Africa

Mozambique
none