"I am PM of Pakistan and #WeStandWithGaza #WeStandWithPalestine," Khan posted on micro-blogging website Twitter.
He also carried a critical quote of American anti-imperialism intellectual Noam Chomsky on Israeli treatment of Palestinians.
"You take my water, burn my olive trees, destroy my house, take my job, steal my land, imprison my father, kill my mother, bombard my country, starve us all, humiliate us all but I am to blame: I shot a rocket back," according to the quote.
Khan has earlier condemned the Israeli attack on worshippers at Al-Aqsa Mosque and has urged the international community to take immediate action to protect Palestinians.
At least 53 Palestinians and six Israelis have been killed in spiralling violence as of Wednesday as Gaza-based militants fired hundreds of rockets on Israel since Monday evening.
Israel has carried out hundreds of airstrikes at Hamas and Islamic Jihad targets in the coastal strip.