Russia could set its sights on Moldova to prevent it from "leaning to the West," following the conflict with Ukraine, the top NATO commander warned Wednesday.

Speaking to US lawmakers at a Capitol Hill hearing, General Philip Breedlove said Moldova could be a target for Moscow.

"What we should do is watch first where we see a strong information campaign picking up, and that is happening in Moldova and other places," he said, in answer to a question on what country Russia might target after Ukraine.

"Russian troops in Transnistria are there to keep Moldova from leaning to the West," Breedlove told the House Armed Services Committee, referring to the breakaway state between Moldova and Ukraine.

The commander also said the conflicts between Russia and separatist rebels in Ukraine could continue.

"I don't think any of us can be sure that Putin has accomplished his objectives inside Ukraine," he said.

The Republic of Moldova, which lies between Ukraine and Romania, has a population of 3.5 million people.

Pro-European parties triumphed in the last elections over pro-Russian rivals.