President Bush wrote the grieving wife of a missing Chinese pilot as top aides cautioned China that ending the standoff over a downed spy plane was essential to avoid further straining relations between the two countries.

On Monday, the ninth day of the standoff, two American officials met with the 24 crew members for 40 minutes. Brig. Gen. Neal Sealock, the military attache at the U.S. Embassy in Beijing, said the crew are "in excellent health and their spirits are extremely high." "They are well taken care of," Sealock said.

The Americans have been held by the Chinese since their crippled EP-3E surveillance plane made an emergency landing on Hainan island in southern China April 1 after colliding with a Chinese fighter jet. The Chinese pilot is missing.

The public anguish of Ruan Guoqin, the wife of the missing pilot, has fueled tensions between the two countries as she accused Bush and his administration of being "too cowardly" to apologize for the loss of her husband.

Bush and other top U.S. officials tried on Sunday to balance their sympathy for her with tough reminders to Chinese officials that the standoff is damaging relations between the two countries.

"I don't want to put a timetable on it; every day that goes by without having it resolved raises the risks to the long-term relationship," Vice President Dick Cheney said on NBC's "Meet the Press."

Administration officials were careful to avoid spelling out specific consequences of further delay in sending the 24 Americans home, but repercussions in Congress were possible. Lawmakers cited a possible trade fight later this year and an upcoming decision on U.S. weapons sales to Taiwan.

"From what I have heard, it is just common sense that the Chinese intransigence is putting a very serious strain on our relationship with China," Rep. Henry Hyde, R-Ill., said Monday on ABC's Good Morning America. He is chairman of the House International Relations Committee.

Hyde, who last week had wondered aloud whether the crew members were hostages, dropped any doubt. "If you look up the definition of hostages, I don't see what else you can describe our 24 crewmen as. They're being held against their will to accomplish some purpose and the purpose evidently is to humiliate us before the world by making us apologize," he said.

Cheney rejected used of the word "hostage," noting that the United States has access to the crew and they are being treated well.

Secretary of State Colin Powell said he was "sorry" about the personal loss experienced by the pilot's wife, using a word top administration officials had avoided. But Powell made clear the United States will not apologize for the collision it says took place in international air space.

"We have expressed regrets, we've expressed our sorrow, and we are sorry that a life was lost," Powell said on Fox News Sunday, referring to the missing pilot. In comparison, he offered this explanation for the U.S. position on an apology to Beijing for the collision: "The question of apology is something quite different, because then we are being asked to accept responsibility. And that we have not done, can't do, and therefore won't apologize for that."

Bush's letter was sent Sunday to the U.S. Embassy in Beijing, which would forward it to the Chinese Foreign Ministry for delivery to the pilot's wife, the White House said. The text of the letter was not made public. "The purpose of the letter is to respond in a humanitarian way, in an American way, to a widow who is grieving," Powell said. "Whatever you think about the politics of it, she's lost her husband."

Diplomats kept up pressure for daily access to the detained crew members, after they were allowed to see only eight of the 24 on Saturday. "We have clearly said to the Chinese that we want access to our people and we want unfettered access to our people," White House national security adviser Condoleezza Rice said on CNN's Late Edition.

Bush spent the weekend at Camp David, the presidential retreat in Maryland, conferring with aides, including Rice and senior adviser Karen Hughes. Rice said Bush had not personally called Chinese President Jiang Zemin because that is an option he can use one time and "one wants to use when it really might make a difference."

Some lawmakers suggested the standoff over the detained crew members was related to broader tensions between China and the United States.

"I think they're pawns being used by the Chinese to try to gain some goals that they're not going to achieve," said Sen. Carl Levin, D-Mich. The Chinese have been concerned about issues such as U.S. arms sales to Taiwan and a proposed anti-missile shield.

Frustrated that the impasse was dragging on, some members of Congress have said it could lead to a bitter fight later this year if Congress is asked to extend trade benefits to Beijing; possible U.S. opposition to China's bid to stage the Olympics in 2008; and affect an arms package Bush is now considering for Taiwan, which China considers a renegade province.

In Taiwan, President Chen Shui-bian told Sen. Jay Rockefeller, D-W.Va., early Monday that he hopes the U.S. standoff with China "will not have any influence" on a weapons deal.

Rice said the standoff has heightened tensions on both sides.

"The Chinese government should not underestimate on this side either the feeling of the American people that this was an emergency landing of a crew that was in distress, and that we now need to resolve this," she said.