The White House on Thursday expressed regret that Henry Kissinger was able to get more of an audience in Beijing than some sitting U.S. officials, after the former top diplomat held talks in China.

Kissinger — an architect of normalizing ties between Washington and Beijing in the 1970s as secretary of state and national security advisor in the administrations of Presidents Richard Nixon and Gerald Ford — was welcomed warmly as an "old friend" by Chinese President Xi Jinping on Thursday amid efforts by Beijing and Washington to mend frayed ties.

The White House said it was aware of the trip but that it was a private visit by a citizen.