Trans-Jordan Arab LegionCAIRO, Saturday, May 15 (UP)-Upwards of 30,000 trained Arab troops had massed on three frontiers of Palestine for an invasion, according to observers here.

It was expected that Egypt, Trans-Jordan and Iraq would provide nearly all the troops for the Palestine invasion. Syria was expected to send a modest force and Lebanon a token one. It was reported that little Yemen, and also Saudi-Arabia, would send some men to show Arab solidarity.

About 3,000 men of the Trans-Jordan Arab Legion had been on duty with the British Army in Palestine as police.

Some of these made what might be called a token withdrawal when British troops evacuated southern areas of Palestine. But they turned back again after crossing the Allenby Bridge over the Jordan. Many of them never even pretended to leave and those who had been in Trans-Jordan all along are reported in Palestine now.

A United Press Aman dispatch said that the bulk of the Legionnaires crossed the Jordan hills and disappeared into the Judean Hills with their artillery, armored cars and a few light tanks. They entered an Arab-earmarked area.