BRUSSELS, June 28 (Reuters) - The European Commission will extend by 18 months its approval for weed-killer glyphosate, used in Monsanto’s Roundup, Health Commissioner Vytenis Andriukaitis said on Tuesday.

“The Commission will follow our legal obligation. We know very well that we have a deadline of June 30. We will adopt an extension for glyphosate of 18 months,” the Commissioner told a news conference.

The EU licence for glyphosate expires at the end of June and, if not extended, would force manufacturers to phase-out products containing the common herbicide within six months.

Contradictory findings on the carcinogenic risks of the chemical have pitted farming and chemical lobbies against citizen and environmental groups, making some EU politicians reluctant to approve its continued use.

The Commission - after failing to win support for a proposal to renew the licence for glyphosate for up to 15 years - had offered a 12 to 18 month extension pending further scientific study. (Reporting By Philip Blenkinsop; editing by Barbara Lewis)