Republican presidential candidate Mitt Romney is to criticise US President Obama on foreign policy, calling for a "change of course" in the Middle East.In a speech, he will lambast the White House over an attack in Libya that killed the US ambassador.
He will also pledge to put Iran "on notice" over its nuclear plans, and call for arms to go to Syrian rebels.
With four weeks to go before the election, polls show Mr Obama retains a foreign policy lead over his rival.
The former Massachusetts governor will deliver a speech at the Virginia Military Institute at 11:20 (15:20 GMT) on Monday.
It will be Mr Romney's first major policy speech since the candidates met on Wednesday for their first face-to-face debate, on the US economy. Mr Obama was widely seen as having "lost" the debate after a hesitant performance in Denver.
Their vice-presidential running mates Joe Biden and Paul Ryan will debate on Thursday.
Libya reactions Mr Romney has repeatedly criticised the president for a foreign policy that he believes has left the US less respected and less powerful in the world.
According to extracts of his speech, Mr Romney will link the deadly attack in Benghazi, Libya to the president's foreign policy.
"The attack on our consulate in Benghazi on September 11, 2012, was likely the work of the same forces that attacked our homeland on September 11, 2001," Mr Romney will say.
"This latest assault cannot be blamed on a reprehensible video insulting Islam, despite the administration's attempts to convince us of that for so long."
It was initially believed the outgrowth of a protest against an anti-Islam film made in the US.
But since the attack, the Obama administration has said that the attack in Benghazi, which killed US ambassador to Libya Chris Stevens and three others, involved some people "linked to groups affiliated with, or sympathetic to al-Qaeda".
Mr Romney was criticised at the time after saying that the administration appeared to "sympathise with those who waged the attacks" before the situation in Libya and at another protest in Egypt became clear.
The White House has faced repeated questions over the security situation in Benghazi in the run-up to the attack.
On Monday, US media reported that Ambassador Stevens wanted a specialised security team to stay past their August deployment, but that the staff was told to make-do "with less".
A state department official told ABC News that embassy's security officer never made a specific request for the team to stay and that there was no net loss of security personnel.
Arms to opposition?
According to the extracts, Mr Romney - whose foreign affairs team includes advisers from the "realist" and "neo-conservative" wings of the Republican establishment - repeatedly accuses Mr Obama of being soft in foreign affairs.
He is particularly tough on the administration's policy in the Middle East, asserting: "Hope is not a strategy".
On Iran, Mr Romney is expected to say he "will not hesitate to impose new sanctions on Iran" and will work with Israel to further co-ordinate military assistance with the country.
"For the sake of peace, we must make clear to Iran through actions - not just words - that their nuclear pursuit will not be tolerated.".
On Syria, Mr Romney will also say the his administration would work "with our partners to identify and organise those members of the [Syrian] opposition who share our values and ensure they obtain the arms they need to defeat Assad's tanks, helicopters, and fighter jets".
Correspondents say that the Syrian and Iranian sections of the speech appear broadly similar to policies already promoted by the Obama administration, but the tone of the speech as a whole is likely to be highly critical.
Ahead of the speech, the Obama campaign released an ad highlighting Mr Romney's gaffe-laden international trip this summer as well as his response to the Libya attack.
"We're not going to be lectured by someone who has been an unmitigated disaster on foreign policy," Obama campaign spokeswoman Jen Psaki said on Monday.