Iran admitted yesterday that Iraqi troops penetrated about half a mile through its lines east of Basra on Thursday, but said its forces had killed or captured all the attackers.

The assertion came in a statement by the speaker of Iran's parliament, Ali Akbar Hashemi Rafsanjani. He also described a separate Iranian advance Thursday on the central front as a "limited action," Deutsche Presse-Agentur reported.

The Iraqi News Agency, meanwhile, said that Iraqi forces had begun mopping-up operations on the central front.

Tehran radio reported continued fighting yesterday, but did not say where it took place. Quoting a military communique, it said that two Iraqi counterattacks on positions earlier captured by the Iranians had failed at a cost of 500 Iraqi lives.

As usual, there was no independent confirmation of either side's claims, and the communiques left it unclear whether Iran gained ground at Meimak or was repelled. Both sides, however, appeared to agree that the battle was not part of any major offensive.

In the southern Persian Gulf, meanwhile, an Iranian F4 Phantom fighter-bomber fired rockets into a Panamanian-registered diving support ship, the 1,538-ton Pacific Prospector, east of Bahrain, setting it ablaze and killing two persons, according to Pentagon sources in Washington. The sources said a U.S. Navy helicopter lifted the crewmen from the burning ship to the frigate USS Stark, which was about 20 miles away.