According to Bolton, being "tied to a monopoly supplier" could come at a "more than economic cost" to Ukraine.
"Why Europe would voluntarily tie itself even more to Russian energy supplies? One alternative there for Ukraine and for other countries is to look for other sources of natural gas," Bolton told reporters.
He went on to suggest such potential sources as Azerbaijan, Israel, "and a variety of other natural sources, including right here in Ukraine, which does produce natural gas," also emphasizing the United States' own "capacity to export liquefied natural gas."
"There could be American or other international energy companies that might find it attractive to explore and drill here in Ukraine," Bolton added.
Bolton's remarks come amid the United States' widely publicized opposition to the Nord Stream 2 gas pipeline. The country claims that the project envisages European reliance on Russian gas.
In late June, US State Secretary Mike Pompeo said that the US government was actively trying to convince its European partners to abandon the development of Nord Stream 2.
Nord Stream 2, the joint venture of Russia's energy giant Gazprom and France's Engie, Austria’s OMV AG, UK-Denmark’s Royal Dutch Shell, and Germany's Uniper and Wintershall, is expected to start operating by end of 2019.