The US military conducted ''freedom of navigation'' operations against 13 countries last year, including India and China, according to an annual Pentagon report.
In the report for the period 1 October 2014 to 30 September 2015, the Pentagon said it exercised its right of freedom of navigation multiple times against India, China, Indonesia, Iran, Libya, Malaysia, Maldives, Oman, the Philippines and Vietnam.
The US military also carried out single operations against Argentina, Nicaragua and Taiwan, the report said.
Freedom of navigation is a principle of international law under which, apart from certain exceptions, ships flying the flag of any sovereign state shall not suffer interference from other states.
''Prior consent required for military exercises or manoeuvres in the EEZ (exclusive economic zone),'' the Pentagon report said on India.
On China, it said maritime claims included excessive straight baselines; jurisdiction over airspace above the EEZ, restriction on foreign aircraft flying through an Air Defense Identification Zone (ADIZ) without the intent to enter national airspace; domestic law criminalizing survey activity by foreign entities in the EEZ; prior permission required for innocent passage of foreign military ships through the territorial seas (TTS).
In 2014, the US had challenged territorial claims of 18 countries including India, China and Brazil.
While China claims that the US is unnecessarily targeting it, the Pentagon says it conducts freedom of navigation operations around the world.
Such operations involve sending navy ships and military aircraft into areas where other countries have tried to limit access.