Obama to nominate Lew for Treasury secretary on Thursday

President Obama will nominate White House Chief of Staff Jack LewJack LewLew: Senate must pass Puerto Rico bill now This week: Zika, Puerto Rico fights loom ahead of recess Fed, Group of 7 monitoring markets after Brexit vote MORE to be his next Treasury secretary Thursday afternoon, a White House official said.

Obama will make his announcement during an East Room event at 1:30 p.m., the official said, adding that Tim Geithner, the current Treasury secretary, will be in attendance at the announcement.

The White House official noted that Lew has "an impressive record of service in both the public and private sector" for more than 30 years.

The president's decision comes on the heels of the year-end "fiscal cliff" negotiations and ahead of fresh fights over the nation’s debt ceiling, sequestration cuts and a measure to continue funding the government.

Sources familiar with the nomination process say Lew has a deep knowledge of both domestic and international economic issues.

Lew, who led the Office of Management and Budget and was a deputy to Secretary of State Hillary ClintonHillary Rodham ClintonHuffington calls for GOP to dump Trump with 'Trexit' WATCH LIVE: Clinton campaigns with Warren in Ohio Clinton: SCOTUS decision a 'victory' for women MORE, also had a significant role in working with officials overseas during the European debt crisis.

It remains unclear if Lew will be confirmed right away. Some Republicans hope to make him answer for what they see as the administration’s tough negotiating tactics in past battles over the budget. 

On Wednesday, Sen. Jeff SessionsJeff SessionsTrump hopes for boost from Brexit vote GOP senators: Brexit vote a wake-up call Sessions warns of 'radical' Clinton immigration policy MORE (R-Ala.) indicated he would oppose the nomination, saying in a statement that Lew “must never be secretary of Treasury.” 

Sessions charged that Lew misrepresented Obama's 2012 budget, saying it did not add to the debt.

"His testimony before the Senate Budget Committee less than two years ago was so outrageous and false that it alone disqualifies," said Sessions.