Top US commander arrives in Pakistan amid tensions
Gen Mattis, US Army Central Command chief responsible for overseeing operations in Iraq and Afghanistan, is on his second visit to Pakistan in less than three months. He last visited the country in July.
He will hold talks with Gen Kayani and other top military leaders.
Mattis arrived in Pakistan at a time when the country`s relationship with the US is at a new low after top American defence officials accused the ISI of supporting the Haqqani network of the Taliban, blamed for two recent attacks on the US embassy and a military base in Afghanistan.
The US says the Haqqani network operates from Pakistan`s North Waziristan tribal region.
Pakistan denies ties with the Haqqani network, while the head of the group, Sirajuddin Haqqani, has claimed it is more secure in Afghanistan than Pakistan.
US Defence Secretary Leon Panetta has threatened unilateral action against the Haqqani network and other Pakistan-based militant groups, a statement condemned by Islamabad as contrary to the spirit of bilateral anti-terror cooperation.
Top Pakistani leaders, including Prime Minister Yousuf Raza Gilani and Gen Kayani, have rejected allegations by US officials and asked the US to avoid hurting the sentiments of Pakistanis.
Gilani has said he will convene a meeting of the political leadership to discuss the situation arising out of the US allegations and threats, according to officials.
Opposition parties have asked the government to convene a special session of Parliament on the US threats and review the relationship with the US.
President Asif Ali Zardari has convened a National Assembly session on October 3 and parliamentary sources said the US threats are expected to dominate the proceedings.