Japanese Foreign Minister Masayoshi Ito today said U.S. explantions of how a U.S. nuclear submarine rammed and sank a Japanese freighter last week were unconvincing.

He made his remarks as a chorus of politicians and press editorials also deplored the accident.

Sharp questions from opposition and government party members in the parliament and strong newspaper editorials accused the U.S. submarine's crew of failing to attempt to rescue the surviving Japanese crew members, whose ship sank in international waters 110 miles from Japan Thursday.

Under questioning, Ito said he had doubts about the U.S. explanations and said he had asked U.S. ambassador Mike Mansfield about them.

Ito said International law clearly required the American submarine crew to make a rescue attempt, and he added that the U.S. explanations of this so far were not convincing.

But he said, "We should await the result of the investigation" planned by the United States.

That inquiry gets underway Tuesday when a veteran Navy submarine commander, Capt. Willis Rich, arrives here from Pearl Harbor. He will question officiers of the submarine, which has been ordered in from sea to an undisclosed port to facilitate the investigation, U.S. officials said. Japanese surviving crewmen also will be questioned, they added.

Mansfield, in a news conference, said, "I feel very distressed about this." He said the investigation should be conducted "the quicker the better, but it must be thorough and justice must be even-handed."

Mansfield added, however, that the accident should not affect the overall U.S.-Japanese security relationship.

The fleet ballistic missile submarine USS George Washington rammed the keel of a 2,300-ton freighter, the Nissho Maru, Thursday morning. The captain and a crewman apparently drowned, and 13 survivors drifted in lifeboats for 19 hours.

The U.S. Navy said the sub, which suffered only minimal damage, surfaced to give assistance but saw no vessel or survivors in distress and then submerged. There has been no explanation for a 35-hour delay in notifying the Japanese government definitely of the accident.

The sinking and accounts of surviving crewmen have become a major public issue and have provided some of the sharpest anti-American press commentary in several years. It has given critics of the U.S.-Japanese security relationship a new platform. The extent of political damage, Japanese officials said, would depend on the results of the U.S. investigation and the resulting explanations.

The accident also provided a new cause for Japan's vociferous antinuclear organizations, which staged a protest march to the American Embassy here.

There was still no explanation of why the submarine was operating near the surface -- at periscope depth -- in foggy weather in a busy shipping lane. Capt. John F. O'Connell, naval attache at the U.S. Embassy, said it may have been surfacing for a navigational reading, to receive radio messages or to make contact with a plane involved in its operations.

Press criticism centered on the alleged failure to save lives and the long delay in reporting the accident to Japanese authorities.

There was considerable press speculation that the sub had avoided picking up survivors intentionally to avoid revealing military secrets.

Similar charges came from opposition members of parliament, led by the Japan Socialist Party, but a member of the ruling Liberal-Democratic Party, Shintaro Ishihara, also raised skeptical questions.

Ishihara asked for a fuller explanation of why the American submarine was operating in those waters and said the accident, if not more completely explained, would affect adversely the U.S.-Japanese security relationship.

Questions were also raised about the statements of surviving seamen that, after nearly five hours in lifeboats, they saw two submarine periscopes emerge from the water and seemingly circle them for some time. U.S. officials said today they had no information on which to base a reply to those assertions.