New York ? The war in Iraq was good news to the cable news channels, which saw substantial gains for the second quarter of the year. But holding on to those gains in the slow news month of June proved difficult.

Fox News Channel continued to dominate its cable rivals, according to Nielsen Media Research numbers released Tuesday, with an average total-day audience of 1.3 million viewers for the April-through-June quarter. That was up 109 percent from a year ago, marginally surpassing Fox’s first quarter this year, which at the time was the channel’s record.

CNN followed with an average 790,000 viewers, up 58 percent from a year earlier. It was a record second quarter for CNN, but 17 percent below the first three months of this year.

Third-place MSNBC, with an average of 399,000 viewers, gained 61 percent year-to-year, but fell 13 percent from the January-to-March period.

Toward the end of the quarter, the news wasn’t so good. Despite the continuing saga of who killed Laci Peterson, which has been a hot topic for cable with less news coming out of Iraq, viewers started to tune elsewhere in June, as all three networks dropped from their May figures.