U.S. Defense Secretary Ash Carter said Wednesday the U.S.-led coalition has not agreed to cooperate with Russia in the fight against the Islamic State and no collaboration is possible as long as Moscow continues to strike other targets.

He said the U.S. will conduct basic, technical talks with Russia about efforts to ensure that flights over Syria are conducted safely, and, "That's it."

Carter spoke during a press conference in Rome with Italian Defense Minister Roberta Pinotti.

The United States, Carter said, is not prepared to cooperate with a strategy of Russia's that is "tragically flawed."

"They continue to hit targets that are not ISIL," Carter said, using an acronym for the Islamic State group. "We believe that is a fundamental mistake."

Carter said he is concerned about the Syrian ground offensive that began Wednesday backed by Russian airpower. Russia, which backs Syrian President Bashar Assad, has hit Western-backed rebels fighting Assad. The U.S. maintains that the only route to peace in Syria is to remove Assad from power.

Russia on Tuesday informed the United States that Moscow is willing to continue talks to ensure that the two countries' aircraft don't interfere with each other, U.S. officials said. But a Russian defense official said the talks should be much broader than what the Pentagon is seeking.

The Pentagon wants talks aimed at making sure there are no conflicts, collisions or other problems as the U.S.-led coalition and the Russians fly over Syria. The U.S. side has proposed a number of safety measures, including using specific international radio frequencies for distress calls by military pilots flying in Syrian airspace.

Carter had called on Russian leaders to contact the Pentagon immediately to discuss Moscow's military activities in Syria, reflecting urgent concerns about Russian aircraft violating Turkish airspace. NATO on Monday denounced Russia for "irresponsible behavior" for allowing its warplanes to cross into Turkey.

Russian Deputy Defense Minister Anatoly Antonov said the Russians want broad discussions on international cooperation between Russia and the U.S.-led coalition fighting the Islamic State, but "regrettably, the Americans would like to limit our cooperation to technical issues relating to interaction between our pilots."

U.S. and Russian officials met once by video conference late last week, before Russian incursion into the airspace of Turkey over the weekend.

Carter and other NATO defense ministers are expected to discuss how to deal with the problem when they meet in Brussels Thursday.

The U.S.-led coalition has been routinely conducting airstrikes on Islamic State militants in Syria.

Russia says the airstrikes it began last week are directed against the Islamic State group, as well as al-Qaida's Syrian affiliates. But the U.S. and France say at least some of the strikes appear to have hit Western-backed rebel factions fighting government troops, with the real goal of protecting Assad.

On a weeklong trip to Europe, Carter is focused on reassuring European allies of U.S. support as they face growing security threats from a more aggressive Russia and militant extremists from north Africa.

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Associated Press writer Vladimir Isachenkov in Moscow contributed to this report.