BUDAPEST--Central European oil and gas firm MOL Nyrt, and Slovakian pipeline operator Transpetrol upgraded the Friendship oil pipeline between Hungary and Slovakia, the companies announced Monday.

MAIN FACTS:

- The companies spent $80 million on the renovation and the capacity expansion of the Adriatic oil pipeline, which now has an annual capacity of 6 million metric tons versus the earlier 3.5 million tons.

- The upgrade enables MOL to meet the oil demand of its refinery in Bratislava from the Adriatic Sea. This improves Hungary's and Slovakia's supply security and decreases their dependence, MOL said.

- The 128-kilometer section with extended capacity may also contribute to the Czech Republic's supply security as the country's refineries can receive crude oil from a new source.

Write to Veronika Gulyas at veronika.gulyas@wsj.com; Twitter: @VeronikaGulyas1