CAIRO, April 24 (Reuters) - U.S. Defense Secretary Chuck Hagel underscored Washington's military commitment to Egypt on Wednesday and pledged American support as Egyptian forces evolve to address new and shifting security threats, U.S. defence officials said.

"I wanted to stop in Egypt to ... reaffirm American commitment to Egypt's emerging democracy, encourage the democratic and economic reforms that are underway here," Hagel told reporters after a day of meetings with Egyptian officials.

"This is a large country, an important country. They are undertaking the right course of action - human dignity and freedom and democratic norms and governance. We are committed to helping any nation that does that," he said.

After stops in Israel, Jordan and Saudi Arabia, Hagel discussed military cooperation and the civil war in Syria with President Mohamed Mursi and Defence Minister Abdel Fattah al-Sisi.

But the U.S. Congress is divided over continued aid to Cairo as the Muslim Brotherhood consolidates its grip on power.

Treasury Secretary Jack Lew did however express support on Wednesday for granting an International Monetary Fund loan to Egypt, saying it was in U.S. interests for Egypt to be on a more sustainable course.

U.S. defence officials said Hagel discussed a full range of issues with Sisi and Mursi, including the Camp David peace treaty with Israel, the security situation in the Sinai and the war in Syria. Hagel pledged U.S. support as Egypt's military grows and changes to meet new security threats.

"All militaries evolve as the threat picture changes and as they try to adapt to those threats, they are ... assessing border security, counterterrorism, non-state actors that are a threat to the state," a U.S. defence official said later.

He said the two sides did not talk about specific types of aid but agreed to continue their discussions as the Egyptian military reassesses the threats the country faces.

Egypt has received $1.5 billion a year in mostly military assistance ever since it signed the 1979 peace treaty with Israel, the first between the Jewish state and an Arab state.

Cairo has maintained a "cold peace" with Israel under the Islamist president and U.S. officials say practical security cooperation with both Washington and the Israelis is working smoothly, though political ties are frozen.

Secretary of State John Kerry said this month that the United States was increasingly worried about internal developments in Egypt, which he said was at a "tipping point".

"We share a very real concern in the Obama administration about the direction that Egypt is apparently moving in," Kerry said, citing economic problems, stalled talks on the IMF loan and the absence of dialogue with the liberal opposition.

Hagel's visit was an opportunity for Washington to maintain a dialogue with the Egyptian military, seen as a pro-American guarantor of regional stability during two years of turmoil since the overthrow of veteran U.S. ally Hosni Mubarak.

The United States is due to deliver a new batch of F-16 fighter jets to Egypt soon, diplomats said, but some Republican senators oppose the delivery. Cairo received four of a group of 20 F-16s in January and the rest are due later this year.

General James Mattis, then head of U.S. Central Command which covers the Middle East, told a Senate hearing last month: "The bottom line is ... that the Egyptian military, through a very difficult period, has maintained and even built trust with the Egyptian people."

He said the armed forces had upheld Egypt's international treaties, including with Israel, provided extra security for U.S. ships going through the Suez Canal, and helped keep the Gaza area as quiet as at any time in 10 years through quiet security operations in the Sinai Peninsula.

"I think anything right now that we do that would undercut the trust between the United States, the U.S. military and the Egyptian military would be extremely unhelpful," Mattis said.