UPDATE 1-US FDA warns India's Sun Pharma on plant problems

* Agency found manufacturing problems at New Jersey plant

* Company says working to resolve issues (Adds details from FDA letter, changes dateline from MUMBAI)

WASHINGTON Aug 31 (Reuters) - Regulators have warned the U.S. unit of Indian drugmaker Sun Pharmaceutical (SUN.BO) about manufacturing problems uncovered at a plant in New Jersey, a letter released on Tuesday said.

U.S. Food and Drug Administration inspectors found violations of federal manufacturing standards during an inspection of the Cranbury, New Jersey, plant from late February through late April, the FDA letter said.

For example, the company's production process for gemfibrozil tablets, a heart drug, "is not capable of producing batches of consistent quality," the letter said.

A company response in May "lacks sufficient corrective actions," the agency added.

Sun said in a statement that it plans to respond to the FDA within 15 days and would work "cooperatively and expeditiously" to resolve the matters mentioned in the letter.

Mumbai-based Sun said it maintained its consolidated sales growth guidance for the current fiscal year to March 2011. It said last month it expected to meet its guidance of 18 percent to 20 percent revenue growth in 2010-11.

The FDA posted the letter here. (Reporting Lisa Richwine; additional reporting by Sumeet Chatterjee in Mumbai; Editing by Will Waterman and John Wallace)