First lady Michelle Obama on Tuesday praised a group of immigration-reform advocates who are fasting to draw attention to the issue and pressure Congress to act.

“As families begin to gather for Thanksgiving, I'm thinking of the brave #Fast4Families immigration reform advocates. We're with you. -mo,” tweeted the first lady. Tweets written personally by Michelle Obama are signed “-mo.”

The group Fast for Families is in the 15th day of their hunger strike. The activists have set up a tent on the National Mall and were visited by Vice President Biden earlier in the week.

President Obama has called immigration reform a second-term priority. A comprehensive Senate immigration bill though has not been taken up by the GOP-controlled House. Speaker John Boehner, R-Ohio, has said he will only move on immigration reform through a piecemeal approach.

Obama has suggested he would be open to a piecemeal approach, but said the end result should include all the elements of the Senate’s bill, including a pathway to citizenship for illegal immigrants already in the country.