OSLO (Reuters) -Norway's Finance Minister Jens Stoltenberg said on Tuesday he hopes the country's $2 trillion sovereign wealth fund, the world's largest, can maintain its current investment policy in which about half the assets are invested in the U.S.

President Donald Trump's administration said last week it was "very troubled" by the Norwegian fund's divestment of U.S. construction equipment group Caterpillar ( CAT ), and that it was engaging with Norway's government on the issue.

Based on recommendations from an ethics watchdog, the fund last month said it had sold its Caterpillar ( CAT ) stake due to the company's supply to Israel of bulldozers used in the occupation of Gaza and the West Bank.

Some Trump allies such as Republican Senator Lindsey Graham have said Norway and its fund could risk U.S. sanctions over the decision, including increased trade tariffs or visa travel restrictions on individuals.

"U.S. authorities are well aware of the rules surrounding the Norwegian sovereign wealth fund and its ethics guidelines," Stoltenberg told reporters, adding that recommendations to divest were not subject to Norwegian government review.

"We don't want to politicise this type of individual decisions, we want to continue to have this system that allows us to have a large investment fund where half of the assets ... are invested in the United States," Stoltenberg said.

Caterpillar ( CAT ) has not commented on the wealth fund's divestment.