MUNICH, Feb. 18 (Xinhua) -- U.S. Vice President Mike Pence said Saturday that his country will "strongly support NATO" as European members of the military alliance are worried about security uncertainties arising from possible change in U.S. policy.

Pence told European leaders that he brought a message from U.S. President Donald Trump that the United States will be "unwavering" in its commitment to trans-Atlantic institutions like NATO.

He made the remarks at the ongoing Munich Security Conference (MSC), a major global security forum which originally focused only on transatlantic relations.

"The U.S. is and will always be your greatest ally," he told the audience in the first major foreign policy address for the Trump administration.

Pence's remarks came one day after U.S. Secretary of Defense James Mattis reassured European leaders that the transatlantic bond is "the strongest bulwark against instability and violence" at MSC, stressing that his country's security is tied to Europe.

While seeking to reassure European leaders, Pence also urged NATO members to shoulder their fair share. "NATO requires your commitment as much as ours," he said.

Pence said many NATO allies lack a clear and credible path to increased defense spending and the time to get one is now. The vice president told his audience that President Trump expects the U.S. allies to keep their word on defense spending.

He also vowed that the U.S. would be dominant in the digital world as the country is in the physical world.

Regarding the Ukrainian issue, Pence pledged that the U.S. will "continue hold Russia accountable," even as President Trump is searching for new common ground with Moscow.

This year's MSC, the 53rd of its kind, opened Friday afternoon. Over 500 high-ranking officials from around the world and representatives of international organizations and businesses took part in the three-day event.

First held in 1963, the annual MSC, once dubbed a "transatlantic family gathering," has evolved into an independent forum dedicated to promoting peaceful solutions of conflicts and international cooperation.