U.S. officials have expressed concern that Liberia's military government appears to be backing off from a pledge to hold elections and return to civilian rule.

State Department Counselor Edward Derwinski flew from Europe to Liberia last week to express U.S. concern about election procedures. Derwinski and other officials also have mentioned their concern about the jailing of Liberian politicians.

Sharply underscoring the fears about the return to democratic rule was the announcement Wednesday by leader Samuel K. Doe that an outspoken former Cabinet member will be tried by a special military tribunal.

Former finance minister Ellen Johnson-Sirleaf, a Harvard-educated development economist who has worked for the World Bank and as the Africa representative for Citibank, was placed under house arrest July 31 and transferred to a military stockade Aug. 9.

Doe said at a news conference that she would be tried for statements made last month in Philadelphia that he called "detrimental to the peace and stability" of Liberia. Although Doe refused to specify on what charge Johnson-Sirleaf would be tried, Justice Minister Jenkins Scott said last week that she likely would be tried for sedition.

According to a text made available by a Liberian opposition figure, Johnson-Sirleaf, in her speech to the Union of Liberian Associations in the Americas, called for less government intervention in the economy and a reallocation of resources, particularly from construction of large public buildings to rural development.

Doe also linked Johnson-Sirleaf's centrist Liberia Action Party to an alleged plot to overthrow his government. Liberian opposition sources here said they believed Doe's actions were intended to provide an excuse to postpone legislative and presidential elections, scheduled for Oct. 8 and Nov. 5, respectively.

U.S. officials said yesterday that Doe's comments caused "great concern" and noted that the United States had been encouraging Liberia to return to civilian rule. The U.S. officials noted that so far Liberia had made excellent progress toward that goal.

U.S. officials also expressed concern yesterday about other Liberian politicians who have been jailed in recent months, as well as several leading journalists and 14 students seized last month for allegedly passing classified documents to Soviet diplomats.

Derwinski said Tuesday that he was confident the elections would go on as scheduled but that Washington was concerned about the manner in which they would be held.