The Saudi Arabian government has expelled five expatriates, including two Americans, for their activity in connection with a Christian religion.

The five men were leaders of a Protestant group called Riyadh International Christian Fellowship. It had been ordered to disband last year, apparently because it had become too active and had taken on too high a profile in this Islamic country.

The five were identified as Rev. William Antablin, a U.S. Presbyterian minister serving as a welfare adviser here; Kenneth Smith, a U.S. agricultural consultant; Allen Carter and Terry Finney, both British; and Munis Jabbur, a Lebanese.

The Saudi government has issued no statement on the expulsion so far, but Smith told the Reuter news agency in Bahrain that they were ordered out of the kingdom earlier this week and all already had left.

A U.S. Embassy spokesman confirmed that the two Americans had been deported but said it had no information regarding the reasons for the action. He refused any further comment.

The kingdom, the birthplace of Islam and site of the holiest Moslem shrine, the Kabbah in Mecca, has long barred all Christian and other religious groups from proselyting.

But under an agreement worked out in 1977 between western embassies and the Saudi government, Catholics and Protestants working and living here have been permitted to hold informal services inside homes and behind compound walls provided they do not try to proselytize, keep a low profile and are not formally organized as churches.

There has been no indication the Saudi government intends to abrogate the accord or stop these services.

Precisely what the five leaders of the International Christian Fellowship have done to anger Saudi authorities was not immediately known. However, sources said they had continued to hold services and carry on other activities after they had been told to disband last year.

It appeared the main point of disagreement was over the high profile the fellowship had been keeping at a time when the kingdom's Islamic leaders have been exerting greater influence, particularly here in the capital.

The interdenominational Protestant group had been attracting hundreds of worshipers every Friday, the Moslem sabbath, when its services were also held, according to these sources.