A clandestine antigovernment tract has appeared here, attacking the martial-law rule of President Mohammed Zia ul-Haq and linking it to the United States.

The single-page sheet mimeographed on expensive imported paper in the national launguage of Urdu, goes beyond what many people have been saying privately about the Zia government.

It is apparently the first time anti-Zia criticism has appeared in printed form and it is one further sign of the fragility of the Army-run government, which took power in a coup 2 1/2 years ago and has failed to keep its promise to hold elections.

While many people complain about the lack of elections, the dominance of the Army and the government's inability to improve the economy, the tract attacks the basic Islamic cast of the regime and its major foreign policy stance of opposing last December's Soviet military invasion of neighboring Afghanistan.

Despite what to all appearances is a very strained relationship, the tract links the Zia government with the United States and strongly suggests that an American-supported regime here will be toppled by the people in the same way Iranians overthrew the shah.

Its rhetoric appears to come straight from the Soviet lexicon, and diplomats in the capital city of Islamabad have noted that Moscow's embassy there has been extremely active recently in cultivating press and student groups.

Lahore, the capital of Punjab, Pakistan's most populous state, is known to have a large Marxist cell of intellectuals. "It is almost an article of faith here," said one Lahore resident, "that anyone who is an intellectual has to be a Marxist."

The document asserted that "reactionaries and imperialists are suffering defeats after defeats in this area, and we are sure their days are numbered in this country, too."

It accused Zia of "putting at stake the very existence of this country to protect the interests of the imperialists," who were identified as the United States, China, Israel, Egypt and Saudi Arabia.

The tract was distributed throughout one middle-class neighborhood in this politically active city in the dead of night about 10 days ago and copies are believed to have been widely circulated throughout Lahore since then.

The tract is signed, Revolutionary Democratic Front, a previously unknown group.

At the same time the tract was distributed, antigovernment graffiti -- "friendship with America means the destruction of Pakistan," read one -- began appearing on walls here. These were erased by government workers each morning.

While it is hard to assess the significance of the tract in terms of an organized opposition to the Zia government, observers noted that all political activities have been banned and the press is under strict censorship since Zia canceled the long-promised election in mid-October.

"Under a martial-law regime it is something to distribute a clandestine night letter, even if it is done just once," said one observer.

According to residents here who have seen the original, the tract is well written, the hand-lettered Urdu caligraphy is considered excellent and the paper is of an exceptionally high quality.

The tract accused the Zia government of being "a protege of imperialism, and it considered only the interests of the outside imperialists and its internal supporters dear to its heart" and said that Pakistani soldiers "are being used as cannon fodder" in Afghanistan.

"The Americans are avoiding the use of their own forces. Instead they are using Pakistan," it continued. "It is jeopardizing its own existence, whereas America is simply threatening the boycott of the Moscow Olympics."