By Isabel Coles and Maggie Fick ARBIL/BAGHDAD (Reuters) - Iraq paused its Tikrit offensive on Monday and officials called for more air strikes against Islamic State militants, while an ******r said Kurdish forces sustained two more chlorine gas attacks by insurgents. General Aziz Waisi told journalists the insurgents used chlorine twice during a January offensive west of Mosul and once in a December attack on his military police brigade in the Sinjar mountain area. Waisi said a number of military police - he did **t say how many - were taken to hospital, where blood tests indicated they had inhaled chlorine gas released by the bombs.