Anglican Church envoy Terry Waite said today that he has met with the captors of four Americans in Lebanon and then left to brief the archbishop of Canterbury and consult with U.S. officials on his efforts to free the four.

Waite, a lay representative of the Archbishop of Canterbury, Robert Runcie, told a press conference here before his departure to London that his mission was not over yet but that "positive steps have been taken."

"So far, so good," he told reporters after his clandestine talks with people who he said he was convinced are the kidnapers -- the first known meeting between a western intermediary and the mysterious Islamic Jihad organization.

In Geneva, Secretary of State George P. Shultz met today with Reginald Bartholomew, the U.S. ambassador to Lebanon, and said Bartholomew had told him that "there seems to be more pressure on the situation right now." Shultz said he had asked Bartholomew to fly to Geneva "because we had a sense of some motion" on the efforts to release the four Americans.

White House spokesman Larry Speakes, also in Geneva for talks this week between President Reagan and Soviet leader Mikhail Gorbachev, said that no request had been received for a meeting with Waite but that U.S. officials would be willing to see him in London, Washington or Geneva.

Waite would not say whether he had seen the American captives, but he said he was "satisfied" that the four who recently had written seeking Runcie's intercession were all right.

The four are Terry Anderson, the Associated Press bureau chief here; the Rev. Lawrence Jenco, director of Catholic Relief Services here; and two officials of the American University of Beirut -- David Jacobsen and Thomas Sutherland. There has been no word of another American University of Beirut employe, Peter Kilburn, since his disappearance last December, and Islamic Jihad has said it killed American Embassy official William Buckley, who was seized in March 1984.

Waite, appearing worn and pale, told reporters he had "lengthy contacts" with the kidnapers.

"There is absolutely no doubt at all that I have got through to the right people and that a measure of trust has been established," he said. "There are many things that I am not prepared to comment on at this time, and I am afraid that I shall have to keep almost all the information that I have to myself in order to protect lives.

"I will not say at all where I met, with whom I met or what passed between us," he said, warning, "Speculation about any of those points could cost lives. Lives are at risk, and a wrong word or a wrong move could cost lives. I am not being overdramatic, and I would urge you to continue to be careful and not endanger the situation by reporting beyond what I am saying now.

"I am now returning to London to brief the archbishop of Canterbury," he said. "Following that I will meet with members of the American administration. I will travel to Washington or some other destination tonight."

Islamic Jihad has claimed responsibility for the abduction of the Americans, as well as four Frenchmen, and has offered to exchange the hostages for 17 prisoners imprisoned in Kuwait after being convicted in fatal bombings there.

No details were disclosed on whether Islamic Jihad's conditions for releasing the Americans had changed.

Since arriving here Wednesday, Waite has warned journalists repeatedly not to follow him, insisting that this could jeopardize the lives of the hostages, their captors and himself.

He said today that his "position as an independent envoy has been honored and respected," and he thanked those who "provided for my security during the past week. At all times I have been treated with courtesy and kindness."

The Reagan administration has said it would not negotiate with "terrorists on concessions" but that it was ready to communicate with the captors of the Americans to facilitate their release.

A package of letters by the four captives, addressed to President Reagan, Runcie, the families of the hostages, U.S. members of Congress and the world press, were delivered to the offices of a western news agency here on Nov. 8. In the messages, the four appealed to Reagan to act and asked Runcie to intercede on their behalf.