Polish authorities said today that Solidarity leader Lech Walesa had been freed from the government villa where he was being held in detention, but mystery surrounded his movements and as of late tonight he had not surfaced.

Semiofficial sources said he was taken by car from Arlamow, the town in a mountainous region near the Soviet border where he had been held, to the nearby town of Rzeszow. From there he was variously reported to have flown here or to his hometown of Gdansk.

The government announced Thursday that Walesa, who had been taken into custody 11 months ago upon imposition of martial law, was being released after writing a conciliatory letter to Gen. Wojciech Jaruzelski, the country's martial-law ruler. Walesa also had sought a meeting with Jaruzelski, the government said.

In an indication that martial law may be lifted next month, the Military Council for National Salvation met today and formally requested a meeting of the Sejm Dec. 13. As Poland's national legislature, the Sejm is the body empowered to lift martial law and replace it, if necessary, with decrees giving the government special powers.

Meanwhile, it was learned that Walesa said today in an interview recorded shortly before his release from internment that he wanted "a fair and proper" agreement with the martial-law government.

The 39-year-old trade union leader was speaking to a Polish television interviewer just before he left the government villa at Arlamow in southeastern Poland. He said he felt well but complained about being cut off from the outside world during his internment.

The interview, his first public statement since the imposition of martial law, has not been broadcast yet on Polish television. A partial text was, however, obtained by the Warsaw bureau of ABC News and later made available to Western correspondents here.

The confusion about Walesa's whereabouts reached its height in the evening, when the official Polish news agency PAP sent an urgent story saying that Walesa had been reunited with his wife, Danuta, and their seven children at their home in the Gdansk suburb of Zaspi. Danuta Walesa promptly denied the report to Western journalists camped outside the apartment and PAP later issued what it described as "an embargo" on the news until further notice.

Excitement grew steadily throughout the day in Gdansk with hundreds of well-wishers gathering near Walesa's home. White-and-red Polish flags were hoisted onto the roof of the building, and, inside Walesa's six-room apartment, a banner was erected in the corridor reading: "We want our Solidarity back -- with Walesa at its head."

In the interview with Polish television, Walesa was asked what made him write the letter to Jaruzelski saying that both sides knew each other's strength and suggesting a meeting.

He replied: "I define the situation as one in which an agreement is both possible and highly necessary, an agreement not with me on my knees, but a fair, proper agreement. We -- the government and myself -- all talk about an agreement, but there is something wrong because we are not able to understand each other. We talk about the same thing, but not in the same way."

Walesa's decision to give an interview to Polish television is likely to dismay some of his supporters who regard the state-run service as the mouthpiece for the government's anti-Solidarity propaganda campaign.

An interview given by the chairman of the rural branch of Solidarity, Jan Kulaj, upon his release from internment in May is widely believed to have discredited him in the eyes of many farmers.

In the extract made available today, however, Walesa chose his words carefully. Asked whether the interview was being made by mutual agreement, he replied: "Yes, I have been thinking a long time whether I should or could agree to that since I have been completely isolated from the world for a year."

The interviewer interrupted: "What do you mean completely? You have a TV set in your room."

Walesa: "Yes, I do have a set; it has three channels, one Russian and two Polish. So of course I have that, but it's much worse with the newspapers. I get them from time to time. Also I do not have a radio: I had one but with only one Warsaw channel -- and that is why I do not have a clear view of the situation."

"But as I said I am a man who is for agreement, and I want to do something for all of us, which is why I agreed to give this interview no matter how it comes out. I will always say what I have been thinking and what I think since I have not changed. Nobody forced me to do this interview; I am just the same as when I walked in here."

Asked how he felt, he replied: "I feel like a man who is still interned but thinks already about his home and the great amount of work that is waiting for him."

In reply to a question about his living conditions at Arlamow, he said: "I must say that the conditions were quite good, but not luxurious. There has been some exaggeration; there was not much luxury here. That is why I say that the conditions were good although the climate did not suit me. I have lived by the seaside for a long time and there it was much more humid, so this climate did not suit me. That is why I did not feel well here."

Showing a flash of his old humor, Walesa said in reply to a question about "speculation in the world about your health": "Well, we all ate from one plate so there couldn't have been anything in the food unless everybody had been sacrificed, including everybody who guarded me. I don't think anybody would have been willing to make such a sacrifice."

According to informants who have seen Polish television pictures of Walesa yet to be transmitted, the Solidarity leader has put on a lot of weight during his internment. He was said to have flashed a V-for-victory sign as he got into a car this morning for the drive away from Arlamow.

An adviser to Walesa said that, as far as he knew, neither the Roman Catholic Church nor any of Walesa's former associates in Solidarity had been consulted about the granting of the interview. He said that Walesa effectively was still in government custody, probably near Warsaw, and was likely to be flown to Gdansk tomorrow.

This report could not be confirmed by either the government or other, independent sources. Despite being pestered by Western journalists all day for news of Walesa, official spokesmen refused to say anything beyond statements that he had left Arlamow this morning.

This itself contradicted a report by a Polish television program on Friday night saying that Walesa already had been "released from his place of internment."

One Western correspondent complained: "Tracking Walesa down is like a very convoluted treasure hunt. The clues seem to be going round in circles."

The confusion over Walesa's movements were interpreted by some Western analysts here as evidence of confusion in the government's own ranks about what to do with him. Some senior Communist Party officials insist that, with Solidarity legally dissolved, Walesa simply will become a private citizen. Walesa, however, evidently believes that he still has a political role to play.