The duo, both 26, are from the Walsall area near Birmingham and were detained in the morning.
Another two men, aged 25 and 32, were arrested in the same area on Tuesday on suspicion of similar offences and remain in custody.
Both sets of arrests are connected and are part of an on-going police operation.
West Midlands Police counter-terrorism officers are carrying out searches at a number of addresses in the Walsall area associated with the suspects.