WASHINGTON (AP) – Defense Secretary Donald H. Rumsfeld warned on Tuesday that violence is likely in Iraq leading up to political milestones there but insisted the insurgency is not gaining ground.

He said attacks could come before the scheduled Iraq”s October 15 referendum on a new constitution and before general elections on December 15.

&#34I think it”s reasonable to expect that violence could, again, increase for a time, as it did during the last elections,&#34 he said during a Pentagon news conference.

&#34But given the political progress, that should not necessarily be considered an accurate gauge of the enemy”s future.&#34

He offered no new thoughts on when U.S. forces might come home in large numbers. He said any decision will be based on commanders” read of the security situation and the capabilities Iraq”s security forces, which now number 173,000. Already, Pentagon officials have said they expect to increase the size of the U.S. force in Iraq before the elections.

Rumsfeld also renewed criticisms of Iran, saying some insurgents” weapons are entering Iraq from there. He indicated it was unclear whether they were coming from elements of the Iranian government or from other parties.

&#34It is true that weapons, clearly, unambiguously from Iran, have been found in Iraq,&#34 he said. &#34It”s notably unhelpful for the Iranians to be allowing weapons of those types to be crossing the border.&#34 He provided no further specifics.

At the briefing, Air Force Gen. Richard Myers, chairman of the Joint Chiefs of Staff, said Iraqi and U.S. forces have detained people who may be connected to the deaths of 20 Marines in two incidents in Haditha, Iraq.

Myers pointed to the arrests as evidence that Iraqi civilians support the U.S.-led coalition trying to pacify the country.

&#34The public came forward and said these are the folks&#34, Myers said. He did not say how many people were detained or identify them but said they are being interrogated to determine their possible involvement. Six Marine snipers were killed by small arms fire on 1 August. Last Wednesday, a Marine armored personnel carrier rolled over land mines, which exploded and killed 14 Marines and a civilian translator.

Myers said the explosives that destroyed the carrier were in three stacked anti-tank mines buried just below the road surface.