KARACHI, Pakistan, April 19 — The Government charged today that “armed Indian nationals” supported by artillery fire from Indian territory at tacked a border post in East Pakistan Friday.

The charge was made public by the Pakistani radio after a formal protest had been handed over to the Indian High Commissioner—the equivalent of an ambassador—in Islamabad, the Pakistani capital.

Another charge against India was contained in a report published here today that Sheik Mujibur Rahman, the East Pakistani political leader who had sought provincial autonomy, would soon be brought to trial.

The Karachi Daily News, an evening paper, said that Sheik Mujib and unidentified “accomplices” would be tried on charges of having conspired “in league with India to secede the eastern wing of the country.”

Officials here say that Sheik Mujib, who was arrested about three weeks ago, is now in detention somewhere in West Pakistan. He was seized when, the Pakistani Army began its attack to suppress the autonomy movement in the East.

The Pakistani authorities hope to win increasing sympathy abroad for their contention that India has been intervening in East Pakistan. The Government says that Indian authorities have been sending arms and infiltrators into East Pakistan to cause trouble but that nonetheless life is returning to normal there. [India has denied these charges.]

[Last Thursday, India accused Pakistani forces of “resorting to unprovoked and heavy firing and adopting threatening postures” in the same border area. Pakistan denied that charge.]

The Pakistani radio said that the attack Friday — on a border post three miles north of Kasba, east of Dacca, the provincial capital — was “an unjustified interference in Pakistan's affairs.”

Unjustified Interference

Pakistan's charges against India figure largely in her appeals for foreign sympathy. At least 17 Moslem or largely Moslem nations are reported here to have voiced sympathy for this Moslem country in what a Rawalpindi paper, The Pakistan Times, calls Pakistan's “struggle to preserve its unity and integrity.”

A voice that carries weight among many conservative Moslems — that of Haj Amin el Husseini, the former mufti of Jerusalem and prominent Palestinian Arab leader before World War Ⅱ—was added to day.

Haj Amin, now retired and living in Lebanon, sent a message to a Pakistani Moslem notable that condemned what he described as India's “open intervention into the internal affairs of Pakistan.” He called on Pakistani Moslems to “spare no sacrifice to preserve the solidarity, integrity and Islamic status of Pakistan.”