This was announced by the U.S. NATO permanent representative Douglas Lute, Censor.NET reports citing The Guardian.
"The recent Russian reinforcements over the last week or so feature a battalion-size ground force... There is artillery, there are long-range rocket capabilities, there are air defence capabilities," Lute told a news briefing on Wednesday. A battalion is typically made up of about 1,000 soldiers.
According to him, Russia's buildup in Syria now included a "considerable and growing" naval presence, long-range rockets and a battalion of ground troops backed by Moscow's most modern tanks.
Moscow had managed a "quite impressive" military deployment over the past week to its Syrian naval base in Tartus and its army base in Latakia, Lute said.
"There is a considerable and growing Russian naval presence in the eastern Mediterranean, more than 10 ships now, which is a bit out of the ordinary," he added.
Washington will not cooperate militarily with Russia in Syria because Moscow's strategy is "tragically flawed," Defense Secretary Ash Carter said Wednesday, in his strongest comments yet on the issue, NBC News report citing Reuters.
"We are not prepared to cooperate in a strategy which as we explained is flawed, tragically flawed, on Russia's part," Carter said during a trip to Rome, renewing U.S. accusations that Russia's strikes were not focused on ISIS militants.
The U.S. is not yet ready to cooperate with Russia in sharing intelligence on ISIL targets, for Washington and Moscow have different goals in the country, the Department of State spokesperson John Kirby said at the press briefing on Wednesday.
"I don't know how you can share intelligence when you don't share a basic, common objective inside Syria," he said.
According to him, the U.S. and Russia have no shared, common objective about going after ISIL.
White House spokesperson Josh Earnest noted that the U.S. continued to wait for official response by Russia to the U.S. proposal on security measures regarding military operations of the country in Syria.
Moscow's growing military involvement in the Syria conflict - which on Wednesday involved its jets backing an offensive by ground troops loyal to President Bashar al-Assad - is expected to be high on the agenda of a meeting of the alliance's defense ministers.
"NATO is ready and able to defend all allies, including Turkey against any threats," Jens Stoltenberg, the organisation's secretary general, told reporters before the Brussels meeting on Thursday,.
"In Syria, we have seen a troubling escalation of Russian military activities. We will assess the latest developments and their implications for the security of the alliance. This is particularly relevant in view of the recent violations of NATO's airspace by Russian aircraft.
"NATO has already responded by increasing our capacity, our ability, our preparedness to deploy forces including to the south, including in Turkey."
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