MEXICO CITY (Reuters) -Mexico’s President Andres Manuel Lopez Obrador offered to help with a key fuel in high demand across Europe, the German president told reporters in the Mexican capital on Tuesday, amid a supply squeeze following Russia’s invasion of Ukraine. President Frank-Walter Steinmeier, Germany’s head of state, made the comments following a meeting with Lopez Obrador. “The Mexican president offered to step up cooperation on liquid gas,” said Steinmeier, without going into further detail. As Russia has progressively cut off natural gas supplies via pipeline to Germany and other Euro…