The US Senate voted Wednesday to tie strings to military aid to Pakistan and stem the spread of shoulder-fired anti-aircraft missiles from Libya as they advanced a massive annual defense spending bill.

The White House has threatened to veto the $662 billion measure over tough new rules requiring military detention of terrorism suspects and affirming that US citizens who join extremist groups may be detained forever without trial.

The Pentagon-funding bill was due to clear the Senate by week's end, touching off negotiations with the House of Representatives to resolve differences between both chambers' versions and send a compromise to President Barack Obama.

The Defense Authorization legislation was seen as a sure bet for passage because it affects US troops in Iraq and Afghanistan, and lawmakers hoped to make it the vehicle for tough new economic sanctions on Tehran.

Republican Senator Mark Kirk and Democratic Senator Bob Menendez offered an amendment meant to cut Iran's central bank from the world financial system, a fresh bid to force the Islamic Republic to freeze its suspect nuclear program.

"Time is not on our side. We must act now or face the consequences of a nuclear Iran," said Kirk, who has rejected warnings that the proposal could sow chaos on global petroleum markets if exports from Iran become inaccessible.

Senators on Wednesday unanimously approved an amendment by Democratic Senator Bob Casey aimed at blocking counterinsurgency aid to Pakistan until Islamabad takes aggressive steps to curb the use of roadside bombs blamed for the deaths of US soldiers in neighboring Afghanistan.

They also adopted an amendment from Republican Senator Susan Collins that calls for US-Libya cooperation to secure slain strongman Moamer Kadhafi's stockpile of some 20,000 portable anti-aircraft missiles.

US officials fear that terrorists could get their hands on such weapons in the chaotic aftermath of Kadhafi's ouster.

Senators also approved Republican Senator John McCain's amendment calling for closer military ties with Georgia, including the sale of weapons he said would help the country, which fought a brief war with Russia in 2008, defend itself.

They also adopted Democratic Senator Jeff Merkley's call for an assessment of the feasibility of accelerating the US troop withdrawal from Afghanistan, where combat operations are now due to end come 2014.

And they approved Republican Senator Roger Wicker's amendment stating that US military chaplains are not required to perform gay marriage.

Senators voted 88-12 to end debate on the legislation one day after they beat back an attempt to strip the detainee rules -- despite warnings from the FBI, the Pentagon, and the US Director of National Intelligence that they risk crippling counter-terrorism efforts.

The controversial measures affirm Obama's right to hold suspected terrorists indefinitely, including US citizens, and calls for Al-Qaeda fighters who plot or carry out attacks on US targets to be held in military, not civilian, custody.

But they allow Obama to decide whether a detainee fits that definition, and permit the government to hold suspected Al-Qaeda fighters in civilian custody after formally declaring that to be in the US national security interest.

Critics have also expressed worries that tough new standards for transferring detainees to other countries -- notably a requirement that top US officials formally declare them no longer a threat -- could hamper the US exit from Afghanistan, where US forces hold thousands of prisoners.

The proposed rules explicitly say that the military detention requirement does not apply to US citizens, but supporters of the legislation stressed that American Al-Qaeda members may be held indefinitely without trial.