Imperial family members, Prime Minister Junichiro Koizumi and others on Sunday extended congratulations to the Imperial parents and grandparents of a baby girl born Saturday to the Crown Princess -- the first baby in her 8 1/2-year marriage to the prince.

The Crown Prince visited the Crown Princess and their newborn baby Sunday morning at the Hospital of the Imperial Household. In the afternoon, the Emperor and Empress also visited them at the hospital for the first time since the baby's birth.

"The baby looked very healthy, although I could not hear her cry," the Emperor told reporters after visiting the hospital for about 30 minutes.

The princess has been recovering rapidly since the delivery and has been walking inside the hospital. She left her bed to see off the Emperor and Empress, according to officials of the hospital, which is located inside the Imperial Palace compound.

Koizumi told reporters before leaving his official residence to go to the Imperial Palace that the celebrations throughout the country "show that the (baby) has been much awaited."

Koizumi was joined by the House of Representatives Speaker Tamisuke Watanuki, House of Councilors President Yutaka Inoue and Supreme Court Chief Justice Shigeru Yamaguchi in making the congratulatory visit to the palace.

State ministers, Supreme Court justices, prefectural governors and ambassadors from various countries signed books of congratulation at the Imperial Palace and the Togu Palace, the residence of the Crown Prince and Princess.

Meanwhile, the Imperial Household Agency began accepting signatures in congratulatory books outside the Imperial Palace shortly after 9 a.m., instead of the initially scheduled 1 p.m.

The Imperial Household Agency said it had accepted signatures from about 6,800 people as of 2 p.m.

At the Kyoto Imperial Palace in the nation's ancient capital, the agency had accepted signatures from about 8,600 citizens as of 4 p.m.

In Hayama, Kanagawa Prefecture, where an Imperial villa is located, about 700 people gathered at a park to celebrate the birth of the princess with chorus singing and drum performances.

Shinichiro Yanagi, head of the committee organizing the event said, "I hope for good health for the Crown Prince's family and that they will visit Hayama soon."

At the port of Yokohama, some 100 vessels sounded their horns in celebration of the baby's birth, and two vessels from the Yokohama fire department sprayed seawater dyed red and white into the air.

After entering the hospital late Friday evening, the Crown Princess gave birth to the baby, who weighed 3,102 grams and measured 49.6 cm tall, at 2:43 p.m. Saturday in what doctors later described as an "extremely smooth and easy delivery."

The birth of the girl to the 37-year-old Crown Princess and the 41-year-old Crown Prince is expected to prompt debate about whether the 1948 Imperial House Law, which says that only a male offspring can ascend the Imperial Throne, should be revised to allow the nation to have a reigning empress.

All the children born to the royal family since the 1965 birth of Prince Akishino, the younger brother of the Crown Prince, have been girls.

Asked to comment on the issue Saturday evening, Prime Minister Junichiro Koizumi ruled out an immediate revision to the law, saying that the matter needs careful consideration.

Bushes send regards

WASHINGTON (Kyodo) President George W. Bush and first lady Laura Bush have sent greetings to the Emperor and Empress as well as the Crown Prince and Princess, congratulating them on the birth of a baby girl, a White House official said Saturday.

The message from the president and the first lady, which will be delivered via the U.S. Embassy to Japan on Monday, congratulates the Imperial family on behalf of the people of the United States.

The Bushes also said in their message that this is a wonderful day for Japanese people and they want to convey their heartfelt joy to the Imperial family, according to the official.