United Nations officials reported that morning and night sessions of the General Assembly's Political Committee had been arranged to accommodate a debate that may last well into the week.

The exchange began when Cuba charged that the United States was responsible for the dawn bombing of three Cuban airfields yesterday. The united States denied the accusation and said the pilots had defected from the Cuban Air Force.

A Cuban source said that Dr. Raul Roa, Cuban Foreign Minister, who castigated the United States yesterday, was ready to deliver his charges at length tomorrow in the Assembly's main political body.

Stevenson Will Reply

Adlai E. Stevenson, United States delegate, also was expected to speak tomorrow.

Meanwhile, some African and Latin-American diplomats sought support for resolutions calling on the United States and Cuba to reconcile their differences. One draft would invite members of the Organization of American States to lend their support.

The Latin-American proposal, which has been undergoing revisions for more than a week, has the United States' backing. It is sponsored by nearly a dozen nations that maintain diplomatic relations with Cuba.

In that it calls on members of the O.A.S. to "lend their assistance" in achieving a peaceful solution, the draft is nearly identical with a resolution adopted last summer by the Security Council.

Since the United Nations has sidestepped disputes arising from the mounting United States-Cuban discord. An appeal for action made by Cuba last fall was put off by the Assembly until the present resumed session. The Council declined to take any action in response to a similar Cuban proposal in January.

Draft Proposal Backed

The United States' backing for the draft proposal, it was reported, came only after indications that some African nations were drafting a resolution less to its liking in that it stresses the reconciliation idea. The United States has maintained that the dispute is not between the United States and Cuba but between Cuban groups. President Kennedy made the point last week and Mr. Stevenson repeated it here yesterday.

There also will be a regular Assembly meeting tomorrow night, beginning the last week of the current Assembly session.

Weary delegates stayed late last night to conclude a two-week debate on the Congo issue. The approved three resolutions calling again for the evacuation-but without a time limit or sanctions-of all Belgian and other foreign military and paramilitary personnel and advisers, maintaining Secretary General Dag Hammarskjold's role in the Congo, urging the convening of the Congolese Parliament and setting up two new bodies.

Lumumba Inquiry Mapped

One of the bodies, a seven-member conciliation commission to be named by the Assembly President, was charged with assisting Congolese leaders to "achieve reconciliation." It's functions will parallel those of a similar commission that recently spent several weeks in the Congo.

The other panel set up last night is a four-member commission that was instructed to examine the circumstances surrounding the death of former Premier Patrice Lumumba and his colleagues.

United States sources indicated that they were pleased with the results of the debate. Other diplomats voiced satisfaction that the Assembly had refused to lay down a deadline for Belgium to withdraw her nationals or to suggest that members invoke sanctions against her if she failed to comply.

The mild resolutions, approved after a long series of votes that lasted until nearly 9 P.M., were thought to contain no important changes in instructions for officials running the United Nations operation in the Congo.