On Saturday, 17 January 2009, Israel announced a unilateral ceasefire, conditional on elimination of further rocket and mortar attacks from Gaza, and began withdrawing over the next several days. Hamas later announced its own ceasefire, with its own conditions of complete withdrawal and opening of border crossings. A reduced level of mortar fire originating in Gaza continues, though Israel has so far not taken this as a breach of the ceasefire. The frequency of the attacks can be observed in the thumbnailed graph. The data corresponds to the article "Timeline of the 2008–2009 Israel–Gaza conflict", using mainly "Haaretz" news reports from 1 February up to 28 February. The usual IDF responses are airstrikes on weapon smuggling tunnels.