The highest ranking officer of the US armed forces, Admiral Michael Mullen, is arriving here later on Thursday for a two-day visit to hold talks ahead of American President, Mr Barack Obama's New Delhi trip in November and also push for three defence pacts between two countries.

Mullen, the chairman of the joint chiefs of staff, is expected to hold parleys with the defence minister, Mr A.K. Antony, the National security adviser, Mr Shivshankar Menon, and other top Indian military brass, officials said.

But official sources said the inking of the three military agreements was unlikely as New Delhi was "unsure" if signing the pact related to military logistics, technology safeguards and geospatial information would indeed benefit it because of some "misgivings".

The three pacts are the Logistics Support Agreement (LSA), the Communication Interoperability and Security Memorandum Agreement (CISMOA) and the Basic Exchange and Cooperation Agreement for Geospatial Cooperation (BECA).

The sources said the "deadlock" over the agreements may figure in the parleys between Mullen and Indian officials.

The US has been maintaining that without signing the CISMOA and BECA agreements, it won't be possible for it to supply high-tech avionics and electronics to India like the one required for the Indian Navy's new Boeing P8-I long-range maritime reconnaissance aircraft.

The aircraft will come armed with new generation US AN/APY-10 radars to give them the capability to provide ultra-high resolution of targets over sea and land.

The new radars, made by US defence and aerospace major Raytheon, are scheduled to be received by 2012 to be installed on the P-8I aircraft.

"The logistics agreement is surely a non-starter. India also has some misgivings about the other two pacts," an official told IANS.

The LSA, if signed, will enable the Indian and American militaries to provide logistics support, refuelling and berthing facilities for each other's warships and aircraft on barter or an equal-value exchange basis.

The official said the pact is "politically contentious" for India.

"The two countries share a good defence relationship, but India doesn't want to be seen as America's direct military ally."

The pact, source said, is tilted towards the US because its forces operate more in the region.

India also wants the US to remove some Defence Research and Development Organisation labs and defence Public Service Undertakings figuring in the America's Export Administration Regulations (EAR) "entity list" which contains the names of foreign firms that are subject to specific license requirements for the export, re-export and/or transfer of specified items.

Mullen's visit also comes at a time when India is nearing to conclude the process to select one of the six foreign aviation majors for the supply of 126 fighters to the Indian Air Force — a lucrative $10 billion deal. Two American companies, Boeing and Lockheed Martin, are among the bidders.

The two countries are also finalising the biggest Indo-US defence deal worth $3 billion for the supply of 10 C-17 Globemaster-III giant strategic airlift aircraft. This will overtake the $2.1 billion contract for the P-8I aircraft inked last year.

Mullen is also expected to discuss volatile situation in the Afghanistan-Pakistan region.