KUALA LUMPUR (AP) - Activists warn a free trade pact being negotiated by the United States and 11 Asia-Pacific nations will impose aggressive intellectual property rules that restrict access to affordable medicines in developing nations.

Nations negotiating the pact will hold an 18th round of talks in Malaysia from July 15, with a goal of completing negotiations by October.

Fifa Rahman, from the Malaysian AIDS Council, say talks have been held in secret but leaked drafts of the agreement show Washington has proposed a tough intellectual property regime that will enhance patent and data protections for pharmaceutical companies and obstruct competition from cheaper generic versions of drugs.

Doctors Without Borders said on Wednesday the pact, billed as a model for future trade agreements, could set damaging precedents with serious implications for developing nations.