By Wesley Bruer and Kelly Mena, CNN

(CNN) -- The Texas State Senate advanced a far-reaching elections bill early Thursday with several provisions placing new restrictions on the voting process, particularly for those living in densely populated counties.

The vote on Senate Bill 7 was 18-13 after more than seven hours of debate and several amendments to the legislation. The final language of those changes is not yet available online for CNN to review.

The amendments introduced on the floor by Republican state Sen. Bryan Hughes during the debate referenced making changes to controversial measures included in the initial bill language on poll watchers, voting hours, disability verification and the number of county polling locations.

The bill would ban drive-through voting and limit extended early voting hours.

The measure would also give partisan poll watchers broader authority when observing at a polling location, including being allowed to record a voter who receives assistance while filing out their ballot.

Democrats and voting rights activists have sounded alarms over the legislation, calling it suppressive and noting that it appears to directly target voting methods used by Harris County, which includes the heavily Democratic city of Houston.

Republicans have said the bill is about election security and integrity, even though Texas already has some of the most restrictive voting laws in the nation and there is no evidence of any widespread fraud.

The state already requires that a voter provide an eligible reason to vote by mail: be 65 or older, people with disabilities or illness, those confined to jail or those who will be out of the county during the election. The bill would also prohibit local election officials from sending out unsolicited absentee ballot applications or encouraging a voter to fill out an application to vote by mail, even if they qualify.

The legislation now heads to the Texas House of Representatives for committee consideration.