"He (Obama) should take this opportunity to seek full Pakistani cooperation with the US-led mission in Afghanistan and our broader counter-terrorism efforts in the region," Senator Marco Rubio said in a statement as Obama met Sharif in Oval Office.
Rubio said Pakistan must fulfil its obligations to deny safe haven to all terrorist groups and take action against those who aid, support and abet them.
"Continued US security assistance should be conditioned on Pakistan's actions against militants that seek to destabilise Afghanistan and threaten the US, as well as steps Islamabad takes to support accountable, civilian governance," he said.
He said in addition to discussing security cooperation, Obama must make human rights issues a priority in his discussions with Sharif.
"Pakistan should enforce its laws equally, giving women and religious minorities the full protections they deserve," he said.
"In particular, it is long past time for Islamabad to repeal Pakistan's harsh blasphemy laws, which unjustly carry a death sentence and enable extremists to blackmail and intimidate their opponents. Prisoners on death row for this 'crime' should be released immediately," Rubio said.