President Mobutu Sese Seko said yesterday that he may arm and train opponents of the Marxist government in neighboring Angola in retaliation for the aid Angola gave rebels who attacked Zaire's Shaba Province last month.

"Everyone believes we should do the same toward Angola . . . But I haven't taken a decision on that subject," Mobutu told reporters.

In fact for several years Mobutu has been aiding two pro-Western guerrilla groups that lost Angola's civil war to a Soviet-Cuban-backed movement headed by Agostinho Neto who is now president of Angola.

Mobutu said he has won a promise from President Kenneth Kaunda of Zambia to intervene in the future to stop rebels from using Zambian territory to hit targets in the Shaba copper belt.

In a meeting with Western reporters, Mobutu admitted that the Zairian army had displayed cowardice when the rebels attacked Kolwezi in Shaba. He said he had ordered the formation of an elite strike force to take over security in the area.

"Security," he said, "will be related to the ability to strike back."

The elite unit will take over the duties of the seven-nation African force now being established to protect the mineral-rich Shaba Provice.

In a related development, witnesses said the army has started rounding up suspected rebel sympathizers in Shaba's capital, Lumbumbashi. An estimated 25 persons were reportedly taken into custody and flown off to an army base at Kamina.

In the Netherlands, Chinese Foreign Minister Huang Hua said yesterday that the Soviet Union had "engineered" the rebel invasion and pledged Peking's support "to oust the Soviet Union and Cuba from Africa."

Huang, on a surprise visit to The Hague to drum up support against growing Soviet and Cuban influence in Africa following his five-day visit to Zaire, said the Kremlin was trying to outflank Europe by starting a series of 'undisguised acts of aggression" in the Middle East and Africa.

Meanwhile, Vice Premier Teng Hsiao-ping expressed China's support for the multi-nation force being sent to Zaire at a dinner Thursday night in Peking honoring President Juvenal Habyarimana. Teng's speech was studded with sharp attacks on the Soviet Union, prompting a walkout by the Soviet ambassador and seven envoys from states allied with Moscow.

U.S. Defense Secretary Harold Brown authorized 25 more flights by the U.S. planes ferrying the African force into Shaba Province and bringing the French Legionnaires out.