The Defense Department issued a formal protest to China on Wednesday over its refusal to permit US Navy ships to enter the port of Hong Kong on two occasions last week. "We are expressing officially our displeasure with the incident," the department's press secretary Geoff Morrell told reporters. He said a Chinese military officer who is Beijing's defense attache in Washington was called to the Pentagon to accept the protest from an Asian specialist. Morrell called it an "a formal protest, an official protest, complaint," for refusing port entry for two US Navy minesweepers and, later, for the USS Kitty Hawk and its accompanying battle group. Also, the Chinese foreign minister met with President George W. Bush on Wednesday and blamed the incident on "a misunderstanding." Morrell said that it is not yet clear whether the Chinese military officer will indeed heed the summons to come to the Pentagon. Morrell said the summons constituted the official protest, but he did not release the wording. Navy officials have said they are most troubled by China's refusal to let the two Navy minesweepers enter Hong Kong harbor to escape an approaching storm and receive fuel. The minesweepers, the Patriot and the Guardian, were instead refueled at sea and returned safely to their home port in Japan. In addition, the Chinese also refused to allow the Kitty Hawk, a US aircraft carrier, to make a planned port visit to Hong Kong. The Kitty Hawk, which has its home port near Tokyo, was forced to return early to Japan when Chinese authorities at the last minute barred the warship and its escort vessels from entering Hong Kong harbor. Hundreds of families of sailors aboard the Kitty Hawk had flown from Japan to spend a US holiday weekend in Hong Kong, but had to return home after China refused the port entry. Later Chinese officials said the Kitty Hawk could enter the port, but by then the carrier had left the area and did not return. On Tuesday, two of the Navy's top admirals said that China's refusal was surprising and troubling. "This is perplexing. It's not helpful," Adm. Timothy Keating, commander of US Pacific Command, told reporters in a videoteleconference from his headquarters at Camp Smith, Hawaii. He also called it distressing and irritating but later said it should not be viewed as "calamitous." "It's not, in our view, conduct that is indicative of a country that understands its obligations as a responsible nation," he said, adding that he hopes it does not indicate a lasting blockage of port visits. China's foreign minister, in the meeting with Bush, blamed "a misunderstanding" for the refusal to allow a flotilla of US warships to make a port call in Hong Kong for a holiday visit. Bush raised the issue with Foreign Minister Yang Jiechi when he visited the White House for talks about North Korea, Iran and other issues. The incident added an unusual twist to China-US relations, strained in recent months by disputes over trade and Iran's nuclear program. "Foreign Minister Yang assured the president that it was a misunderstanding," White House press secretary Dana Perino said. She said she could not explain the nature of the misunderstanding. The aircraft carrier USS Kitty Hawk and members of its strike group, including a nuclear submarine, were scheduled to dock in Hong Kong for a four-day visit. At the same time hundreds of sailors' families had flown to the city to spend the holiday with loved ones, dozens of Americans living in Hong Kong had prepared turkey dinners for those without relatives. Hong Kong has long been a favored port of call for the US military but Beijing's approval has been required since July 1, 1997, when Britain handed this former colony back to China. Hong Kong's Marine Department, which handles logistic arrangements for ships docking in Hong Kong's deep-water port, said it had not received the documentation it normally would receive from other agencies clearing the arrival of foreign military ships.