BEIJING -- Premier Li Peng, whose martial-law order for troops to clear Tian An Men Square of student protesters resulted in hundreds, perhaps thousands, of deaths, appeared publicly Thursday for the first time since the weekend massacre and briskly praised soldiers for a job well done.

The government also issued a new set of martial-law regulations, that appeared to foreshadow a renewed crackdown on student dissidents--something that was borne out today when troops moved in and raided Beijing University.

United Press International and Cable News Network both reported students being detained by security forces. UPI also reported that American and British television crews were detained briefly today in separate incidents, one of which involved covering the Beijing University raid.

UPI quoted Chinese witnesses as saying that government forces entered the university, ripping from walls and boards of the main courtyard anti-government posters and graphic photographs of shattered bodies of students and other protesters killed in last weekend's assault on Tian An Men Square. At least a dozen students were reportedly arrested.

Elsewhere in Beijing, foreigners continued to flee the city as various governments sent in specially chartered jets to collect them. Although the capital seemed to show some signs of returning to normal, the occasional gunshot could still be heard.

Li's televised appearance added weight to word that hard-line, conservative Communist Party leaders had emerged victorious in a power struggle with reformists who sympathized with student demands to open China's political system. Li's chief rival, disgraced Communist Party chief Zhao Ziyang, has been neither heard from nor officially spoken of for three weeks.

"You have worked hard, comrades," Li told a group of soldiers at an indoor meeting. Raising his arm and voice at once, he encouraged the troops "to continue working hard to protect the capital's safety and order."

The soldiers applauded as Li strode out of the room. There had been reports that Li was wounded in the leg Sunday in an assassination attempt. He showed no signs of injury during the television clip which, according to the news announcer, was taped Thursday morning.

Li, wearing a Mao jacket rather than the Western-style suit and tie often favored by the reformists, appeared with Vice President Wang Zhen, a conservative former army general best known for violently subduing the far western Xinjiang region in 1949, at the beginning of Communist rule in China.

The new martial-law rules banned the building of barricades, and government radio broadcast telephone hot-line numbers to which citizens were told they should report activities of "counterrevolutionaries."

This morning, Hong Kong newspapers predicted that house-to-house searches of activists on a government blacklist were planned for this weekend.

One government edict referred to student activists and leaders of embryonic independent trade unions as "important members of the counterrevolutionary turmoil."

The terminology marked the latest step in a steady demonization of the pro-democracy movement. For a while, the government had referred to the students as "patriotic" and blamed demonstrations on manipulative officials high up in the Communist Party.

One leader of the seven-week-long pro-democracy student demonstrations that provoked the present crisis has been detained, United Press International reported. Many student leaders are believed to be in hiding.

At least five military trucks carrying soldiers passed near Beijing University on Thursday night and paramilitary police set up cordons on roads leading to the area.

"I think they're trying to arrest people but cannot find them," a Western diplomat in Beijing said. "I think they are trying to get people like (Beijing University student activist) Wang Dan and the others, to arrest them and show them on television. They will (be forced to) say on television that they worked under Zhao Ziyang's orders, or something like that."

More Foreigners Leave

Foreigners continued to flee the city on special flights out of Beijing airport. Some Western and Asian diplomats indicated that the mass evacuation of foreigners, while prompted by genuine security concerns, was also meant to convey a strong political message to the Chinese government that diplomatic and economic ties will inevitably suffer if the hard-liners who ordered the weekend massacre remain in control of the government.

"This is meant by most countries as a clear political sign that we are not going to maintain a large diplomatic presence to talk with people who did what they did," one Western diplomat said. "It's a sign to China's leaders that they are not going to get away with it cheaply."