WASHINGTON (AFP) The US Congress this week may approve tough new restrictions on military aid to Pakistan, which has decried similar curbs on economic assistance as undermining its sovereignty, aides said Wednesday. The fresh limits include efforts to track where US military hardware sent to Pakistan ends up, as well as a warning that US aid to Pakistan must not upset the balance of power in the region - a reference to tensions with India. The limits are in a 680-billion-dollar US Defence Department spending measure for 2010 that the Senate will take up after the bill cleared the House of Representatives in a 281-146 vote on October 8. If, as expected, the Senate approves the legislation, it will go to US President Barack Obama to sign into law - and could worsen a flare-up between Washington and Islamabad about stings attached to US aid dollars. Pakistan has bitterly complained about restrictions in US legislation aimed at tripling non-military aid to 7.5 billion dollars over five years, denouncing some of the limits as attacks on its sovereignty. US lawmakers have increasingly called for closer tracking of US aid to Pakistan, amid growing concerns about US strategy in Afghanistan as Obama weighs sending more troops to fight the eight-year-told war. The military spending bill would impose new restrictions on how Pakistan gets reimbursed out of a 1.6-billion-dollar fund for logistical and military support of US-led efforts to battle Islamist insurgents. The measure requires that the US secretaries of state and defence certify that whether such reimbursement is consistent with the national security interest of the United States and will not adversely impact the balance of power in the region. The bill also says the Pentagon must certify that Islamabad is waging a concerted fight against Al-Qaeda, the Taliban, and other fighters before it can receive monies in a 700-million-dollar package to aid Pakistan battle extremists on its soil. The measure also directs the Pentagon to track how Pakistan uses military hardware it receives in order to prohibit the retransfer of such defence articles and defence services without the consent of the United States. The legislation also calls for the White House to send lawmakers a report every 180 days on progress toward long-term security and stability in Pakistan. The Senate is expected to hold a procedural vote on the legislation on Thursday, aides said. Democratic Senator Robert Menendez and Republican Senator Bob Corker crafted the new restrictions.