MOSCOW - The Kremlin on Tuesday dismissed accusations of Russian air forces in Syria attacking hospitals, calling the allegation unacceptable and baseless.

"We categorically deny and do not accept such statements, especially because those who make such statements are unable to prove their allegations in any way," Kremlin spokesman Dmitry Peskov told reporters.

He asked reporters to rely on primary sources of information over such issues, noting that for the Russian side the primary source should be official representatives of the Syrian authorities.

"In this case, the representatives of the Syrian authorities made a number of statements on this subject, and declared their position as to who might be behind these bombings," RIA Novosti news agency quoted Peskov as saying.

Syrian ambassador to Moscow, Riad Haddad, on Monday accused the U.S. of destroying a hospital backed by the humanitarian group MSF (Medecins Sans Frontieres, or Doctors without Borders) in Syria.

"American warplanes destroyed it (a hospital in Syria's northwestern province of Idlib). Russian warplanes had nothing to do with any of it -- the information that has been gathered will completely back that up," Haddad told TV channel Russia 24.

In another development, Defense Ministry spokesman Igor Konashenkov said that Turkey has been using large-caliber artillery against the Syrian army and opposition forces since the end of last week.

Ankara has also attacked border settlements in Syria's Aleppo province, he said in a ministry statement.

Konashenkov also warned of the sharp upsurge in terrorist activities "in particular northern areas" after the Munich agreement on cessation of hostilities in Syria was reached Friday.

Turkish authorities as well as Western countries have been blaming Russia for bombing civilian targets.

Moscow denies such allegations and insisted that all Russian airstrikes in Syria are carried out after repeated verification of reconnaissance information and through coordinated actions.