REITs prices are dropping all time low today. I am into long term investment for REITs, would you guys suggest to buy in now or wait for 1 to 2 weeks more?

If you are into long term investment, it does not really matter if you purchase now or later since you know that the REITs that you are purchasing (assuming you have DYODD and have done sufficient research into the financial statements of REITs you are purchasing knowing that they will survive) will ultimately recoup back to its original value in a matter of few years time.

Alternatively you can do DCA and make purchases in fixed period intervals without having to worry about timing the market or not . However, do note that by doing so may incur relatively higher brokerage fees for every transaction you make via online brokerages. Another method you may try is to opt for OCBC's BCIP program and do DCA to REIT ETF every month for DCA with lower charges.