WASHINGTON (Reuters) - President Donald Trump’s former campaign manager Paul Manafort offered to post more than $12 million in real estate and life insurance assets and to limit his travel in a bid to avoid continued house arrest, according to court documents filed on Saturday.

Paul Manafort, former U.S. President Donald Trump 2016 campaign chair (R), departs after a status conference at the U.S. District Court following his indictment on tax fraud and money laundering charges in the special counsel's investigation into alleged Russian meddling in the 2016 U.S. presidential election in Washington, U.S. November 2, 2017. Also seen is Manafort's wife Kathleen (L). REUTERS/James Lawler Duggan

Manafort, who ran Trump’s presidential campaign for several months last year, and associate Richard Gates earlier this week pleaded not guilty to a 12-count indictment by a federal grand jury.

The charges include conspiracy to launder money, conspiracy against the United States and failing to register as foreign agents of Ukraine’s former pro-Russian government. They are part of Special Counsel Robert Mueller’s investigation into alleged Russian efforts to tilt the 2016 election in Trump’s favor and potential collusion by Trump associates.

In the Saturday court filing, Manafort offered to limit his travel to New York, Washington and Florida and pledged life insurance worth about $4.5 million as well as about $8 million in real estate assets, including a property on Fifth Avenue in New York that was identified by some media outlets as an apartment in Trump Tower.

U.S. District Judge Amy Berman Jackson said on Thursday that initial bail terms would remain in place and set a bail hearing for Monday to consider changes. On Friday, she suggested a potential May 7 trial date.

Manafort and Gates are under house arrest, under unsecured bonds of $10 million and $5 million, respectively, which means they do not have to post the bail unless they fail to show up for court or violate other conditions.

Prosecutors have argued there is a risk of flight and both men are subject to electronic monitoring.

As part of the indictment, the special counsel’s office is seeking forfeiture of four of Manafort’s properties in connection with money laundering charges.

Peter Carr, a spokesman for Mueller, declined to comment on Saturday.

Manafort, 68, in the filing also explained why he had three different U.S. passports, a fact noted by prosecutors. Manafort’s lawyer, Kevin Downing, rejected suggestions that Manafort was a “Jason Bourne character” - referencing a fictitious, globe-trotting, rogue covert agent.

“The facts are much more mundane,” Downing wrote.

Manafort had two passports, including one for submitting to foreign governments to receive visas while traveling on the other, his lawyers said. He was issued a third passport because one had been lost and Manafort contacted passport services to advise them it was found.

Downing also wrote that funds Manafort had deposited in accounts on the island of Cyprus were legal and now had only “nominal” balances. Prosecutors said Manafort and Gates used numerous entities to transmit more than $18 million from Ukraine through Cyprus and eventually to the United States.

Federal prosecutors said in a court filing on Tuesday that Manafort’s financial assets were substantial, but difficult to quantify because he listed figures on loan applications and other financial documents since 2012 that ranged from $19 million to $136 million.

The investigation has cast a shadow over the first nine months of the Trump presidency. For Manafort and Gates, a conviction on conspiracy to launder money alone could carry a sentence of up to 20 years in prison.