But Israeli officials say Washington has been instrumental in helping organise shipments of guns and ammunition to the presidential guard from Egypt and Jordan.
It is unclear whether any of the US money would go directly to the Badr Brigade.
At least 10 Palestinians have died in violence between forces loyal to Abbas and those of the governing Hamas movement since his call this month for new elections.
Hamas, which beat Fatah in parliamentary elections in January, said Abbas's call amounted to a "coup".
The sources said Badr's deployment may not start for several months because the force needs substantial amounts of new military equipment and training.
Badr would reinforce Abbas's presidential guard and other Fatah-dominated security services.
The US recently sent an official to visit a Badr training facility in Jordan for informal discussions, a European diplomat and other sources said.
US officials declined to comment on the matter. A military official from a European country visited the base separately to talk to Badr commanders and assess their needs, the sources said.
The US has so far not provided Badr troops with training or equipment, but has assisted with co-ordinating preparations for their deployment, sources said. Israel has signalled support for Badr's deployment.
It has been under US and European pressure to take steps to bolster Abbas after his call for early elections.
Ehud Olmert, the Israeli prime minister, in his first formal meeting with Abbas on Saturday, pledged $100 million in withheld tax revenues to the Palestinian president, bypassing the Hamas-led government.
Analysts say the Badr Brigade is Fatah's best-trained and best-equipped fighting force, aside from Abbas's presidential guard.
Loyal to Fatah
The brigade is considered to be more loyal to Fatah than other forces. It also has strong ties to the Jordanian king.
In addition to equipment, the brigade is seeking funds for salaries.
Western diplomats and Palestinian officials said members of the presidential guard and the Badr Brigade have not received official wages since Hamas came to power in March.
Abbas's presidential guard currently has about 3,700 members.
With aid from the US and its allies, Abbas hopes to expand it to 4,700 members in 12 to 18 months.
Hamas says its own Executive Force has nearly 6,000 members and will be expanded. Hamas receives funding from Iran and other Islamist allies.