A new witness has provided police here with their first clear picture of the man they believe shot and killed Prime Minister Olof Palme last Friday, officials said today.

Police said that a 22-year-old artist, a woman they did not name, clearly saw the face of a man running away from the scene of the crime and has come forward to provide them with a detailed drawing. West German federal police experts in computer reconstruction were to arrive here tonight from Wiesbaden to aid Swedish authorities in making a more detailed picture of the face based on the drawing.

Police appeared to be treating the new witness as a substantial break in an investigation they admit has provided few clues thus far.

A number of persons saw a man running on nearby streets immediately after Palme was killed in downtown Stockholm near midnight on Friday. A taxi driver in his parked cab said he saw someone police believe to be the killer jump into a waiting car that sped away through the city.

But their descriptions outlined only a dark-haired man wearing a black coat. The young woman artist is the only one so far believed to have seen his face well enough to describe it.

Meanwhile, a number of government heads and international political figures have accepted personal invitations from Palme's family and his Social Democratic Party to attend the March 15 funeral here, party officials said. Among them are United Nations Secretary General Javier Perez de Cuellar, Italian Prime Minister Bettino Craxi and Socialist International President Willy Brandt, a former West German chancellor.

Both current Austrian Chancellor Fred Sinowatz and former chancellor Bruno Kreisky have confirmed attendance, along with West German Foreign Minister Hans-Dietrich Genscher and Sam Nujomo, head of SWAPO, the Namibian independence guerrilla group, and French socialist Regis Debray.

Party officials said they expected a broad response to the personal invitation, reflecting Palme's prominence in socialist and social democratic circles, and his international activities in the fields of nuclear disarmament, human rights and redistribution of the world's wealth. During more than three decades of political life, 17 of them as party leader and 11 as prime minister, Palme served in a number of international roles, including as a vice president of Socialist International.

The personal invitations are separate from official word of the funeral sent to most governments, which are expected to send delegations. The United States has not yet announced its delegation but diplomats expect it to be led by Secretary of State George P. Shultz.