Pakistan Thursday said there were "some major differences" with India on modalities of withdrawal of troops from Siachen glacier and the two sides were trying to address them through "intense negotiations".

The two countries were engaged in "intense negotiations to reach an early agreement on withdrawal of troops," a Pakistan Foreign Office spokesman said in a statement reacting to Defence Minister Pranab Mukherjee's remarks in a TV interview that both sides agreed to withdraw troops from their present position, but modalities have to be worked out.

• India, Pakistan to withdraw troops from Siachen: Pranab

The two countries have held several rounds of talks on withdrawal of troops from the world's highest battlefield. The Pakistani spokesman claimed that the two countries came close to signing an accord on Siachen in 1989, "but they did not".

He expressed Pakistan's readiness to sign, referring to the understanding reached in 1989, without any delay, provided the Indian side was also ready to do so.