BRUSSELS (Reuters) - Germany's seasonally adjusted budget surplus was 1.7% of the country's GDP in the second quarter, down from 2.0% in the previous three months, data from the European Union's statistics office Eurostat showed on Tuesday.

Germany has been running large budget surpluses for years and is now under pressure from other euro zone countries, the European Central Bank and the International Monetary Fund to spend more on long-overdue investment to help prevent an economic slowdown in the euro zone's biggest economy.

Unadjusted for seasonal swings, the budget surplus was even higher at 3.2% of GDP, in the second quarter, up from 2.2% in the first three months.

(Reporting By Jan Strupczewski; editing by Philip Blenkinsop)