By Jennifer Liberto@CNNMoneyDecember 2, 2013: 4:21 PM ET
Big defense companies arestepping up their push on Congress to end federal spending cuts.
Northrop Grumman(NOC) CEO Wes Bush warned Monday that his company would be forced to cut more jobs if a second round of sequester, or forced budget cuts, will go through in January. Already, he said the company has been cutting its workforce in recent years.
"When there is less money to be spent, it has implications," Bush said, in a news conference.
Bush was among nearly 110 defense and aerospace CEOs who signed a letter on Monday, warning that the sequester is damaging national security and the economy, and should be put to an end.
"We urge you to do whatever it takes to end sequestration before even greater damage is done to our nation's defense industrial base, technological advantages and national security," said the letter, which defense trade group Aerospace Industries Association sent to the President, the Senate Majority Leader and House Speaker.
Other CEOs who signed the letter include Phebe Novakovic of General Dynamics(GD), Linda Hudson of BAE Systems(BAESY), Dennis Muilenburg of Boeing(BA)'s defense unit and Robert Stevens of Lockheed Martin(LMT).
Bush said Northrop has cut staff by 19% in recent years due to a double whammy of the sequester combined with a pullback in war spending.
The first round of the sequester went into effect in March, slicing $80 billion from both defense and non-defense programs this year.
"Sequester is having a negative impact on research and development that will inevitably slow economic growth," he said.
More budget cuts loom at Pentagon
Large defense companies like Northrop, Lockheed and Boeing are some of the largest spenders on lobbying Congress and federal agencies. Through the end of October, the industry spent $97 million on lobbying this year, according to the Center for Responsive Politics. Northrop Grumman has shelled the most -- $13.2 million. Boeing has spent $11.5 million and Lockheed spent $11.1 million.
Trying to end, or blunt, budget cuts was listed as a top lobbying issue for many companies.
"I think it's important for us all to speak up. . .this represents a slow decay for our country," Bush said, when asked about his company's move to pressure the president and lawmakers to end sequester.