The United States has asked Turkey for permission to send U2 reconnaisance planes into Turkish airspace to help verify Soviet compliance with the new strategic arms limitation treaty to be signed next month.

The flights would be a means of trying to make up for loss of listening posts in Iran that previously had helped U.S. intelligence track Soviet missile tests. They would be one ingredient in the Carter administration's effort to convince Congress that Soviet compliance with SALT II can be verified.

The Turkish Foreign Ministry, in a statement yesterday in Ankara confirming the request, said it has not yet decided whether to accede, adding:

"In response to the United States' request, it has been pointed out that Turkey attaches great importance to SALT II and to its effective implementation. However, since Turkey is not a party to the treaty and as the text is not fully known to her, the subject could be taken up by the authoritative Turkish government bodies only if it is determined by Turkey that the requested contribution advances the objectives and concurs with the understanding of the parties to the treaty."

A U.S. official said last night that this was a "positive statement," although the last line raises some questions.

The independant newspaper Milliyet in Istanbul said the last line meant that before Turkey agrees to the reconnaisance flights, it wants assurances that the Soviet Union would not object to them.

"It has been stressed that while contributing to world peace and security, it is only natural that Turkey also takes into consideration its own security and relations with its neighbors, and takes care to base its relations with its neighbors on mutual trust," the Foreign Ministry statement said.

The Soviet Union and Turkey share a 250-mile land border in eastern Turkey and are divided for hundreds of more miles only by the Black Sea.

The U2s, equipped with special antennas, would fly above Turkey at an angle permitting them to pick up radio messages sent back by Soviet rockets during test flights. The planes, which would not be based in Turkey, also might carry radar or other scanning devices to try following the test flights visually.

Administration officials acknowledge that such flights, possibly from nearby Cyprus, would not fully make up for the loss of the Iranian facilities. But Secretary of Defense Harold Brown repeatedly has said the United States will within a year recover the monitoring SALT II.

Critics of the treaty say Brown's prediction is overoptimistic. One anti-SALT Senate staff aide said yesterday that the U2s would be useful only if they were in the air at the opportune moment-when a Soviet test is under way.

SALT II would require the Soviets to warn the United States in advance of many tests, and administration officials say their spy satellites would detect ground preparations for tests for which advance notification is not required.

The United States also is negotiating with Turkey over continued use of land bases on Turkish soil that serve to monitor Soviet missile activity and Black Sea ship movements. Deputy Assistant Secretary of State Warren Christopher was in Turkey last week trying to work out an extension of the present base agreement, which expires next October.

The Turkish government of Prime Minister Bulent Ecevit is demanding increased U.S. military and economic aid as the price for renewing the accord. It is not known whether the demand for more aid also has been tied to authorization for U2 overflights.

Turkey has forbidden such overflights since the early 1960s.